Selasa, 17 Maret 2015
Selasa, 17 Februari 2015
Selasa, 16 Desember 2014
Aplikasi Kanvas Rem
- Saat kaki menginjak pedal untuk melakukan pengereman, apabila terdengar bunyi-bunyian dan terasa aneh sebaiknya segera diperiksa.
- Kalau pedal diinjak makin dalam tandanya kampas sudah menipis, apalagi bila diinjak sampai mentok baru ada reaksi pengereman.
- Bila pedal diinjak diikuti dengan bunyi berdecit secara terus menerus selama pedal rem diinjak, bisa dipastikan kampas rem harus diganti.
- Bila roda depan dan belakang ikut bergetar saat pengereman biasanya paku klem yang berfungsi mengikat kampas, dipastikan sudah menyentuh teromol.
- Jika dipastikan tanda-tanda tersebut di atas terjadi pada mobil anda, segera bawa mobil anda ke bengkel untuk mengganti kampas remnya agar anda terhindar dari kecelakaan mobil karena rem yang bermasalah.
Selasa, 11 November 2014
Aplikasi product AEC Polymer
Aplikasi product AEC Polymer
As an industrial adhesives manufacturer, our laboratories have developed a new range of structural patented adhesives (industrial glue)
with exceptional performances, without primary or surface preparation.
This range combines a great increase of usual performances and large
flexibility.
Our MSpolymer ®, from the Black Mamba ® range, are single component adhesives and sealants (industrial glue),
without solvent and smell which allow bonding and jointing. They cure
by moisture regain in 12H to 24H. Non toxic for the user (without
solvent or dangerous materials like isocyanate) and environmental
friendly, our MSpolymer ® adhesives are ideal for a wide field of use.
BLACK MAMBA FHG® RANGE: revolutionary
AEC POLYMERS, industrial adhesives manufacturer, has created single component MS Polymer® adhesives with the Faster Higher Green® technology. This technology of industrial adhesives allows jointing of sealing operations by offering an optimum water resistance and air tightness even under pressure.
Many bonding applications are feasible with:
- Glass
- Metal
- Laminated glass/resin
- Tender/stiff woods
Sumber : AEC POLYMER
INDUSTRIAL ADHESIVES MANUFACTURER
SAF RANGE, structural methacrylate adhesives
As an industrial adhesives manufacturer, our laboratories have developed a new range of structural patented adhesives (industrial glue)
with exceptional performances, without primary or surface preparation.
This range combines a great increase of usual performances and large
flexibility.CHARACTERISTICS :
From the flexible range ( 400 %
elongation – 6 MPa ) to the hyperstructural one ( 30 % elongation –
25 MPa ), these structural methacrylate adhesives fit
to an open time from 2 min to 1 H 30. Highly resistant, they resist to
pain powder cycle. Ideal for wide surfaces assembly ( transport,
shipbuilding industry, building, ... ), these structural methacrylate adhesives fits also to mass production.
PERFORMANCES :
Economical, these structural methacrylate adhesives replace
classical assembly solutions and ensure you a considerable amount of
times and a significant increase of your productivity. The exceptional
qualities of these methacrylate adhesives make the
structural bonding possible, allowing thermal expansion, vibrations...
The application, without surface preparation or primary, makes the use
easier for everyone.
APPLICATION FIELDS :
Many fields of use exist as shipbuilding industry, composite, transportation, building, sign industry...
PACKAGINGS :
Our structural methacrylate adhesives have different packagings : 50 mL and 490 mL cartridges, 20 Kg pails and 200 Kg drums.
BLACK MAMBA RANGE, adhesives and waterproof sealants
Our MSpolymer ®, from the Black Mamba ® range, are single component adhesives and sealants (industrial glue),
without solvent and smell which allow bonding and jointing. They cure
by moisture regain in 12H to 24H. Non toxic for the user (without
solvent or dangerous materials like isocyanate) and environmental
friendly, our MSpolymer ® adhesives are ideal for a wide field of use.CHARACTERISTICS :
Their permanent elasticity of these adhesives
and waterproof sealants, allows various assemblies in extreme
conditions. They could be painted contrary to silicones and their
temperature resistance permits the epoxy paint powder cycle ( 200°C
during 20 min ). Our MSpolymer ® adhesives resist to
UV, to humidity and to a wide temperature slot. They are non porous
that’s the reason why no moulds or stains appear on the joints.
PERFORMANCES :
Their adhesive
performance on all materials, dry-cleaned thanks to our T700, their
flexibility and their resistance to all weathering events make them
ideal substitutes to silicones and PU.
APPLICATION FIELDS :
Many fields of use exist for these adhesives and waterproof sealants, as shipbuilding industry, composites, transports, swimmingpools, building, descriptive industry...
PACKAGINGS :
Our MSpolymer ® adhesives have different packagings : cartridges 290 mL, bags 600 mL, buckets 20 kg and drums 200 L.
BLACK MAMBA FHG® RANGE: revolutionary
industrial adhesives
AEC POLYMERS, industrial adhesives manufacturer, has created single component MS Polymer® adhesives with the Faster Higher Green® technology. This technology of industrial adhesives allows jointing of sealing operations by offering an optimum water resistance and air tightness even under pressure.CHARACTERISTICS :
The FHG® MSpolymer ® adhesives
has exceptional characteristics in terms of speed. Indeed, at 20°C with
50% of relative moisture, the skin formation time of these industrial adhesives
is about 10 minutes only and their curing speed is 5mm/24hours. The
shrinkage is about 1%. Moreover, 100% of the active matter reacts during
the curing speed.
PERFORMANCES :
The AEC POLYMERS, industrial adhesives manufacturer, FHG® adhesives
have many amazing characteristics because they offer a high adherence
combined with a high elongation which can go up to 400%. These qualities
are essential to realize bonding which are able to resist to impacts,
vibrations and pealings.
The industrial adhesives MS Polymer® FHG® resist to:
- Fire and smoke resistances. The
product obtained the M1/F1 accreditations (according to the standards NF
F 16-101 and STM-S 001).
- Temperatures > use slot between -40°C to +140°C, without any loss of mechanical properties.
- Freshwater, salted water and demineralised water,including during a permanent immersion.
- U.V without yellowing and without affecting mechanical resistances.
- Agressive environments as the alkalines, the diluted acids, polar solvents, the oils, the humidity.
- Temperatures > use slot between -40°C to +140°C, without any loss of mechanical properties.
- Freshwater, salted water and demineralised water,including during a permanent immersion.
- U.V without yellowing and without affecting mechanical resistances.
- Agressive environments as the alkalines, the diluted acids, polar solvents, the oils, the humidity.
All the industrial adhesives of the MS Polymer® FHG® range can be painted without any surface preparation.
APPLICATION FIELDS :
Our MS Polymer® FHG® industrial adhesive technology do not emit any smell during their curing speed and are solvent, phtalate, isocyanate et silicone free. These industrial adhesives allow to adhere to several supports without primer.Many bonding applications are feasible with:
- Glass
- Metal
- Laminated glass/resin
- Tender/stiff woods
PACKAGINGS :
The AEC POLYMERS industrial adhesives from the MSpolymer ® FHG® range have different packagings : cartridges 290 mL, bags 600 mL and 5 kg, drums 200 L.
LABELLING :
The industrial adhesives MS Polymer© FHG® are not submitted to the legal labelling.
Selasa, 09 September 2014
Conformal Coating
Contents
- 1 Applications
- 2 Coating methods
- 3 Coating Chemistries
- 4 Material considerations
- 5 References
- 6 External links
Applications
Precision analog circuitry may suffer degraded accuracy if insulating surfaces become contaminated with ionic substances such as fingerprint residues, which can become weakly conductive in the presence of moisture. (The classic symptom of micro-contamination on an analog circuit board is sudden changes in performance at high humidity, for example when a technician breathes on it). Furthermore, a suitably chosen material coating has proved to actually reduce the effects of mechanical stress and vibrations on the circuit and its ability to cope in extreme temperatures.For example, in a chip-on-board assembly process, a silicon die is mounted on the board with an adhesive or a soldering process, then electrically connected by wire bonding, typically with .001-inch-diameter gold or aluminum wire. The chip and the wire are very delicate, so they're encapsulated in a version of conformal coating called "glob top." This prevents accidental contact from damaging the wires or the chip. Another use of conformal coating is to increase the voltage rating of a dense circuit assembly; an insulating coating can withstand a much stronger electric field than air, particularly at high altitude.
With the exception of parylene, most organic coatings are readily penetrated by water molecules. A coating preserves the performance of precision electronics primarily by preventing ionizable contaminants such as salts from reaching circuit nodes, and combining there with water to form a microscopically thin electrolyte film. For this reason, coating is far more effective if all surface contamination is removed first, using a highly repeatable industrial process such as vapor degreasing or semi-aqueous washing in a special machine. Extreme cleanliness also greatly improves adhesion. Pinholes would defeat the purpose of the coating, because a continuous contaminant film would be able to make contact with the circuit nodes and form undesired conductive paths between them.
Coating methods
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This section may require cleanup to meet Wikipedia's quality standards. The specific problem is: no images. (April 2009) |
Brush coating
This works by flow coating the material onto the board and is suitable for low volume application, finishing and repair. The finish tends to be inferior cosmetically and can be subject to many defects such as bubbles.[2] The coating also tends to be thicker and unless skilled operators applied the coating, highly subjective in quality.Spray application coating
Conformal Coating Spray booth
One of the key attributes of atomised spraying is giving excellent tip coverage to components. When conformal coatings are applied to a PCB they have a tendency to slump. The first layer of a coating can give a thin edge on the corner of components. This can be countered with a second coat through double dipping or over brushing but this is a repeat process and may not be acceptable. To counter this problem the technique of atomised spraying can be used.
Conformal coating dipping
Conformal Coating Dip System
The issue of "thin tip coverage" where the material slumps around sharp edges can be a problem especially in a highly condensing atmosphere. This tip coverage effect can be eliminated by either double dipping the PCB or using several thin layers of atomised spraying to achieve good coverage without exceeding coating thickness recommendations. A combination of the two techniques may also be used.
Typical robotic processes
This involves needle and atomised spray applicators, non-atomised spray or ultrasonic valve technologies that can move above the circuit board and dispense / spray the coating material in selective areas. Flow rates and material viscosity are programmed into the computer system controlling the applicator so that the desired coating thickness is maintained.[4] This method is highly effective at large volumes as long as the PCBs are designed for the method. However, there are limitations in the select coat process[5] like all the other processes, such as potential capillary effects around low profile connectors which "suck" up the coating accidentally.The process quality of dip or dam-and-fill coating and non-atomised spray technology can be improved when necessary by applying and then releasing a vacuum while the assembly is submerged in the liquid resin. This forces the liquid resin into all crevices, eliminating uncoated surfaces in interior cavities.
The differences in application methods can be seen in a comparison presentation.[6] Choice of method is dependent on the complexity of the substrate to be conformally coated, the required coating performance, and the throughput requirements.
Curing and Drying
Solvent & Water based conformal Coatings
For standard solvent based acrylics, air drying (film forming) is the normal process except where speed is essential. Then accelerated heat curing can be used, using batch or inline ovens / conveyors and using typical cure profiles which are designed for maximally efficient curing without damage to the coating.[7]Water based conformal coatings can be treated in the same manner but with more care with the application of the heat due to the slower drying times.
UV curing UV Conformal coatings
UV Inline Conveyor for curing conformal coatings
This increase in the popularity of UV curable conformal coatings is due to its rapid cure speed, level of processing ease, environmental friendliness and thermal cycling resistance, which have never before been achieved with UV conformal coating materials.[8]
There are different types of UV lights (lamps) used in curing conformal coatings and they are Arc and Microwave lamps.
Thickness & Measurement
Coating material when dry (after curing) should typically have a thickness of 30–130 µm (0.0012–0.0051 in) when using acrylic resin, epoxy resin, or urethane resin. For silicone resin, the coating thickness recommended by the IPC standards is 50–210 µm (0.0020–0.0083 in).There are several methods for measurement of conformal coating thickness and they fall into two categories. These categories are wet film & dry film conformal coating measurements.
Wet Film Conformal Coating Measurement
Wet film gauge for Conformal Coating Thickness Measurement
Applying too much coating can be expensive. Also, wet film measurements are useful for conformal coatings where the dry film thickness can only be measured destructively or over application of conformal coating could be problematic.
The wet film gauges are applied to the wet conformal coating and the teeth indicate the thickness of the conformal coating. The dry film thickness can then be calculated from the measurement.
Dry Film Conformal Coating Thickness Measurement
Dry film Conformal Coating Thickness Measurement
Test coupons are the ideal method for measuring the coating thickness, whether is it spraying or dipping, and can be kept as a physical record of the performance. Apply the coating to the test coupons at the same time as the circuit boards provides a permanent measurement and an accurate guide to the coating thickness.
Thicker coatings or better applied coatings may be required when liquid water is present due to potential microscopic pinhole formation in the coating[2] or when the coating material is too thin on the sharp edges of components due to poor application techniques. This is considered a defect and can be eliminated with appropriate steps and training. These techniques effectively "pot" or "conform" to the components by completely covering them.[citation needed]
Conformal Coating Inspection
Conformal Coating Inspection Booth
Conformal Coating AOI
Recent developments in conformal coating automated optical inspection (AOI) have begun to address these manual processed and issues. Automated Inspection Systems now exist which can be camera or scanner based so the technology can be matched to the project.
Conformal Coating Selection
The selection of conformal coating material is a crucial factor that needs to be considered carefully and in relation to the application method.[9] The wrong selection can not only affect the long term reliability of the circuit board but can cause massive difficulties with both processing and costs.The most common[citation needed] standards for conformal coating are IPC A-610[10] and IPC-CC-830.[11] These standards list indications of good and bad coverage and describe various failure mechanisms such as dewetting[12] and orange peel.[13]
Conformal coating inspection is a critical factor in determining successful coating application and long term reliability of PCBs. Using the IPC standards allows the coating operator to monitor the coating application performance. This can be done manually by the operator in an inspection booth by examining the PCB under white and UVA light or it can be done automatically by a conformal coating inspection system.
Another type of coating called parylene is applied with a vacuum deposition process versus a spray or needle application. The parylene is applied at the molecular level by a vacuum deposition process at ambient temperature. Film coatings from 0.100 to 76 μm can be easily applied in a single operation. The advantage of parylene coatings is that they cover hidden surfaces and other areas where spray and needle application are not possible. Coating thickness is very uniform, even on irregular surfaces. The three main disadvantages are that (i) any desired contact points such as battery contacts or connectors must be carefully covered with an air-tight mask to prevent the parylene from coating the contacts, (ii) it is a batch process and does not lend itself to high volume processing, and (iii) the cost per PCB can be highly prohibitive due to the capital investment costs and the cost per batch.
Coating Chemistries
There are many chemistries of conformal coatings out on the market today. While the "Material Considerations" section below is very important to finding the correct conformal coating, it is also important to find a coating chemistry meeting the application needs. Below are five common strengths for each conformal coating chemistry.[14]- Acrylic
- Ease of rework
- Simple drying process
- Good moisture resistance
- High Fluorescence level
- Ease of viscosity adjustment
- Epoxy
- Useful to about 150C [302F]
- Harder durometer, abrasion resistance
- CTE closer to epoxy PCB substrate
- Higher Tg (Glass transition)
- Good dielectric properties
- Polyurethane
- Good dielectric properties
- Good moisture resistance
- Solvent resistance
- Less reversion potential
- Abrasion resistance
- Silicones
- Stable over wide temperature range (in general, -40C to 200C)[-40F to 392F]
- Flexible, provides dampening and impact protection
- Good moisture resistance
- High dielectric strength
- Low surface energy for better wetting
- Fluorinated or non Fluorinated - Poly-Para-Xylylene (Parylene)
- Excellent uniformity regardless of part geometry
- Chemical inertness
- Minimal added mass and low outgassing
- Low environmental impact process
- Low dielectric constant
- Amorphous Fluoropolymer
- Low dielectric constant
- High glass transition temperature
- Low surface energy
- Low water absorption
- Solvent resistance
Material considerations
Selection of the correct choice of coating material (lacquer) is one of the process engineer's most critical decisions. Criteria for selection must be based on answering many questions, which will include:[16]- What is being protected against? (e.g., moisture, chemicals)
- What temperature range will the electrical device encounter?
- What are the physical, electrical, and chemical requirements for the coating material itself?
- Electrical, chemical, and mechanical compatibility with the parts and substances to be coated (for instance, does it need to match the coefficient of expansion of chip components?)
- How easily can the material be reworked once applied?[17]
- How fast does the material dry (cure)?[18]
- How fast can the material be applied and dried (throughput time)?[18]
- What type of process and equipment is necessary to achieve the required coating quality (uniformity and repeatability)?[19]
- Price of the material per litre.[citation needed]
- Quality of the material supplier (two acrylic material manufacturers will not make equal quality of material).[citation needed]
References
- printed circuit boards assembly at DMOZ
- "Common failure mechanisms in conformal coating: Pin holes,Bubbles and Foam". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Setting up a Conformal Coating Spray Facility". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Conformal Coating Thickness Measurement Systems". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Technical Bulletin September". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Conformal Coating Application Techniques". Slideshare.net. Retrieved 2010-07-26.
- "Thermal profile cure process of a typical solvent based conformal coating". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Bulletin April" (PDF). Retrieved 2010-07-26.
- "Technical Bulletin May". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Acceptability of Electronic Assemblies" (PDF). Retrieved 2010-08-27.
- "Qualification and Performance of Electrical Insulating Compound for Printed Wiring Assemblies" (PDF). Retrieved 2010-07-26.
- "Common failure mechanisms in conformal coating: De-wetting". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Bulletin Jan 09 Conformal Coating failure mechanisms Orange Peel" (PDF). Retrieved 2010-07-26.
- "Conformal Coating Comparison Guide". ElectronicCoating.com. Retrieved 2010-08-18.
- "Basic Concepts Of Conformal Coating". Slideshare.net. Retrieved 2010-07-26.
- http://www.conformalcoatingconsultancy.com/userfiles/july%20newsletter/how%20to%20select%20a%20conformal%20coating%20material.pdf
- "Technical Bulletin June". Conformalcoating.co.uk. Retrieved 2010-08-27.
- "Conformal_coating_drying_and_curing_FAQs". Conformalcoating.co.uk. Retrieved 2010-07-26.
- "Technical Bulletin November". Conformalcoating.co.uk. Retrieved 2010-08-27
Jumat, 29 Agustus 2014
Manfaat Sealant untuk Penambal, Perekat dan Pengisi
Walau bukan material inti saat membangun rumah, sealant
termasuk bahan bangunan yang banyak di cari di pasaran. Material ini berbahan
silikon yang berfungsi sebagai pengisi, penambal, dan perekat. Cara
pemakaiannya cukup mudah. Tinggal buka tutupnya, tempelkan ujungnya ke bagian
yang ingin diisi, dan tekan ke bagian yang ditambal. Bahan ini biasanya
digunakan untuk perekat bagian ujung lantai keramik, ujung parket, pengisi
antar kaca, dan lain sebagainya.sealer pasti udah lekat banget sama dunia
otomotif ya Anda. mungkin semua mobil Anda2 pake sealent!
Tugas dari sealer ini memang simpel, tapi ini sangat berperan penting Anda.. Fungsinya buat menyumpal celah2 dua permukaan biar ga bocor, jadi setiap dua komponen yang disatukan sekecil apapun pasti akan ada celahnya, karena kemampuan rembes dari air dan udara itu bner2 mantap Anda!! belum lagi didukung pressure (tekanan) yang tinggi, celah sekecil apapun bahkan sekelas mikron bisa dirembes walaupun pelan tapi pasti Anda ceritanya pada jaman sebelum diciptakan sealer, solid gasket atau paking sangat diutamakan untuk ngejalanin tugas ini Anda.. dan dipisahan dari jenis bahan dan ketebalan sesuai denAnda kebutuhannya, ada yang bahan kertas/karton, besi, alumunium, kuninAnda sampai gabus..
Mungkin Anda
juga ada yang pernah praktekin bikin sendiri paking dari karton atau
alumunium..
Nah seiring perkembanAnda teknologi sealer kimia / lem sealer ini malah lebih populer dan sangat dibutuhkan untuk jadi pelengkap wajib Anda dalam mengatasi pengamanan celah yang ekstra ketat..
Untuk jenis sealer ini seiring waktu juga menjadi semakin banyak jenis dan fungsnya nih Anda, malah kebanyakan orang awam ga tau juga, mungkin marak informasi di kalanAnda mekanik doang.. itu juga kadang mekanik ga tau semua jenis2 sealer Anda.. contohnya makein sealer khusus waterpump di gardan ,ini bisa jadi pengawalan ekstra yang salah (kegagalan sealer), malah jadi ngerepotin ujung2nya karena harus bongkar2 lagi gara2 ada rembesan atau malah penyumbatan.
Nah seiring perkembanAnda teknologi sealer kimia / lem sealer ini malah lebih populer dan sangat dibutuhkan untuk jadi pelengkap wajib Anda dalam mengatasi pengamanan celah yang ekstra ketat..
Untuk jenis sealer ini seiring waktu juga menjadi semakin banyak jenis dan fungsnya nih Anda, malah kebanyakan orang awam ga tau juga, mungkin marak informasi di kalanAnda mekanik doang.. itu juga kadang mekanik ga tau semua jenis2 sealer Anda.. contohnya makein sealer khusus waterpump di gardan ,ini bisa jadi pengawalan ekstra yang salah (kegagalan sealer), malah jadi ngerepotin ujung2nya karena harus bongkar2 lagi gara2 ada rembesan atau malah penyumbatan.
Rabu, 16 Juli 2014
Kamis, 29 Mei 2014
Brake Bonding
SUBA 3000 mengandung resin sintetis yang mengeras ireversibel pada pemanasan dan sangat cocok sebagai gesekan lapisan perekat Persiapan permukaan
Hubungi Kami
PT. CITRA BARU PERKASA
Tlp : 02153202340
Email : sales@citrabaruperkasa.co.id
Permukaan untuk ditempelkan harus dibersihkan untuk menghilangkan semua partikel kotoran, karat, lemak dan minyak. Selanjutnya disarankan bahwa sepatu rem harus sedikit yang kasar oleh peledakan pasir untuk menjamin ikatan yang baik.
Kamis, 08 Mei 2014
Modeling Board RAKU TOOL
We find solutions for your applications
As
the market leader in board materials, we have developed the world's
largest production operations for styling, modeling, and working board
materials.
You, too, can benefit from our high-performance products:
- High-performance standard range that we can adapt quickly to meet technical requirements on the market
- "Complete package" available, consisting of board material, adapted adhesive and appropriate repair paste
Selasa, 29 April 2014
Silicone Sealant
PENGERTIAN Lem Silicone Sealant merupakan lem multi-fungsi yang dapat
digunakan sebagai lem untuk konstruksi, perekat, dan pengisi celah (
Gap-Filling) pada suatu benda.
KEUNGGULAN
Dapat digunakan di dalam maupun di luar permukaan,
Daya rekat tinggi dan kuat,
Water and weather resistant,
Cepat rekat, dan
Tahan lama.
KEUNGGULAN
Dapat digunakan di dalam maupun di luar permukaan,
Daya rekat tinggi dan kuat,
Water and weather resistant,
Cepat rekat, dan
Tahan lama.
Hubungi Kami :
PT. CITRA BARU PERKASA
PT. CITRA BARU PERKASA
0215302340
sales@citrabaruperkasa.co.id
Minggu, 02 Maret 2014
Industri komponen otmotif
Industri komponen otmotif merupakan salah satu sub sektor industri
yang sangat penting dikembangkan di dalam negeri sejalan dengan upaya
bangsa ini untuk mengembangkan industri otomotif. Sebab, tanpa dukungan
pengembangan industri komponen, maka upaya pengembangan industri
otomotif di dalam negeri akan mengalami ketimpangan.
Karena itu, pengembangan industri komponen dan industri pendukung (supporting industries) lainnya sudah menjadi satu kebutuhan yang tidak bisa dihindari lagi dalam upaya mengembangkan industri otomotif nasional. Bahkan, berdasarkan pengalaman di sejumlah negara lain, dengan berawal dari pengembangan industri komponen maka dapat dibangun sebuah klaster industri otomotif yang kokoh, kuat dan berdaya saing tinggi.
Peranan industri komponen otomotif tidak hanya sekadar untuk mendukung industri perakitan kendaraan bermotor yang membutuhkan sumber suplai komponen yang mencapai ribuan item untuk setiap kendaraan bermotor, tetapi juga untuk mengisi kebutuhan spare parts pengganti di masyarakat konsumen/pemakai kendaraan bermotor yang sering disebut dengan istilah pasar layanan purna jual (after sales service).
Layanan purna jual pada produk industri kendaraan bermotor (dan juga pada beberapa produk manufaktur lainnya) merupakan salah satu faktor penting yang dapat menentukan sukses tidaknya pemasaran sebuah produk otomotif di suatu wilayah pasar. Tanpa dukungan layanan purna jual atau tanpa adanya jaminan ketersediaan spare parts bagi sebuah produk kendaraan bermotor, bagaimanapun bagusnya kualitas produk tersebut, maka tetap saja konsumen tidak akan banyak tertarik untuk menggunakannya. Hanya konsumen tertentu yang tidak rasional yang akan membeli produk tersebut.
Dari sekian ribu jenis komponen yang digunakan pada kendaraan bermotor, komponen rem merupakan salah satu komponen yang sangat vital. Mengingat pentingnya peranan komponen rem pada kendaraan bermotor, maka proses produksi komponen tersebut tidak bisa dilakukan secara asal-asalan. Tetapi harus dilakukan secara teliti dengan pengawasan mutu yang ketat. Hal itu perlu dilakukan agar komponen rem yang dihasilkan betul-betul berfungsi dengan baik, sehingga mampu memberikan jaminan keamanan dan keselamatan bagi pengendaranya.
Karena itu, pengembangan industri komponen dan industri pendukung (supporting industries) lainnya sudah menjadi satu kebutuhan yang tidak bisa dihindari lagi dalam upaya mengembangkan industri otomotif nasional. Bahkan, berdasarkan pengalaman di sejumlah negara lain, dengan berawal dari pengembangan industri komponen maka dapat dibangun sebuah klaster industri otomotif yang kokoh, kuat dan berdaya saing tinggi.
Peranan industri komponen otomotif tidak hanya sekadar untuk mendukung industri perakitan kendaraan bermotor yang membutuhkan sumber suplai komponen yang mencapai ribuan item untuk setiap kendaraan bermotor, tetapi juga untuk mengisi kebutuhan spare parts pengganti di masyarakat konsumen/pemakai kendaraan bermotor yang sering disebut dengan istilah pasar layanan purna jual (after sales service).
Layanan purna jual pada produk industri kendaraan bermotor (dan juga pada beberapa produk manufaktur lainnya) merupakan salah satu faktor penting yang dapat menentukan sukses tidaknya pemasaran sebuah produk otomotif di suatu wilayah pasar. Tanpa dukungan layanan purna jual atau tanpa adanya jaminan ketersediaan spare parts bagi sebuah produk kendaraan bermotor, bagaimanapun bagusnya kualitas produk tersebut, maka tetap saja konsumen tidak akan banyak tertarik untuk menggunakannya. Hanya konsumen tertentu yang tidak rasional yang akan membeli produk tersebut.
Dari sekian ribu jenis komponen yang digunakan pada kendaraan bermotor, komponen rem merupakan salah satu komponen yang sangat vital. Mengingat pentingnya peranan komponen rem pada kendaraan bermotor, maka proses produksi komponen tersebut tidak bisa dilakukan secara asal-asalan. Tetapi harus dilakukan secara teliti dengan pengawasan mutu yang ketat. Hal itu perlu dilakukan agar komponen rem yang dihasilkan betul-betul berfungsi dengan baik, sehingga mampu memberikan jaminan keamanan dan keselamatan bagi pengendaranya.
Epoxy
Epoxy
From Wikipedia, the free encyclopedia
This article is about the thermoset plastic materials. For the chemical group, see epoxide.
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Epoxy resins, also known as polyepoxides are a class of reactive prepolymers and polymers which contain epoxide groups. Epoxy resins may be reacted (cross-linked) either with themselves through catalytic homopolymerisation, or with a wide range of co-reactants including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols, and thiols. These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly referred to as curing. Reaction of polyepoxides with themselves or with polyfunctional hardeners forms a thermosetting polymer, often with strong mechanical properties as well as high temperature and chemical resistance. Epoxy has a wide range of applications, including metal coatings, use in electronic and electrical components, high tension electrical insulators, fibre-reinforced plastic materials, and structural adhesives. Epoxy resin is employed to bind gutta percha in some root canal procedures. [1]
Contents
Epoxy chemistry
Epoxy resins are low molecular weight pre-polymers or higher molecular weight polymers which normally contain at least two epoxide groups. The epoxide group is also sometimes referred to as a glycidyl or oxirane group.A wide range of epoxy resins are produced industrially. The raw materials for epoxy resin production are today largely petroleum derived, although some plant derived sources are now becoming commercially available (e.g. plant derived glycerol used to make epichlorohydrin).
Epoxy resins are polymeric or semi-polymeric materials, and as such rarely exist as pure substances, since variable chain length results from the polymerisation reaction used to produce them. High purity grades can be produced for certain applications, e.g. using a distillation purification process. One disadvantage of high purity liquid grades is their tendency to form crystalline solids due to their highly regular structure, which require melting to enable processing.
An important characteristic of epoxy resins is the epoxide content. This is commonly expressed as the epoxide number, which is the number of epoxide equivalents in 1 kg of resin (Eq./kg), or as the equivalent weight, which is the weight in grams of resin containing 1 mole equivalent of epoxide (g/mol). One measure may be simply converted to another:
Equivalent weight (g/mol) = 1000 / epoxide number (Eq./kg)
The equivalent weight or epoxide number is used to calculate the amount of co-reactant (hardener) required when curing epoxy resins. Epoxies are typically cured with stoichiometric or near-stoichiometric quantities of curative to achieve the best physical properties.
As with other classes of thermosetting polymer materials, blending different grades of epoxy resin, as well as use of additives, plasticizers or fillers is common to achieve the desired processing and/or final properties, or to reduce cost. Use of blending, additives, and fillers is often referred to as formulating.
Bisphenol A epoxy resin
The most common and important class of epoxy resins is formed from reacting epichlorohydrin with bisphenol A to form diglycidyl ethers of bisphenol A. The simplest resin of this class is formed from reacting two moles of epichlorohydrin with one mole of bisphenol A to form the bisphenol A diglycidyl ether (commonly abbreviated to DGEBA or BADGE). DGEBA resins are transparent colourless-to-pale-yellow liquids at room temperature, with viscosity typically in the range of 5-15 Pa.s at 25°C. Industrial grades normally contain some distribution of molecular weight, since pure DGEBA shows a strong tendency to form a crystalline solid upon storage at ambient temperature.
Bisphenol F epoxy resin
Bisphenol F may also undergo epoxidation in a similar fashion to bisphenol A. Compared to DGEBA, bisphenol F epoxy resins have lower viscosity and a higher mean epoxy content per gram, which (once cured) gives them increased chemical resistance.Novolac epoxy resin
Reaction of phenols with formaldehyde and subsequent glycidylation with epichlorohydrin produces epoxidised novolacs, such as epoxy phenol novolacs (EPN) and epoxy cresol novolacs (ECN). These are highly viscous to solid resins with typical mean epoxide functionality of around 2 to 6. The high epoxide functionality of these resins forms a highly crosslinked polymer network displaying high temperature and chemical resistance, but low flexibility. 100% solids hybrid novolac epoxy resin systems have been developed that contain no solvents and no volatile or organic compounds. These hybrid novolac epoxies have been documented to withstand up to 98% sulfuric acid and can be engineered to service temperatures exceeding 400 degrees Fahrenheit.Aliphatic epoxy resin
There are two types of aliphatic epoxy resins: glycidyl epoxy resins and cycloaliphatic epoxides.Glycidyl epoxy resins are typically formed by the reaction of epichlorohydrin with aliphatic alcohols or polyols to give glycidyl ethers or aliphatic carboxylic acids to give glycidyl esters.[2] This reaction is normally done in the presence of an alkali, such as sodium hydroxide, to facilitate the dehydrochlorination of the intermediate chlorohydrin. The resulting resins may be monofunctional (e.g. dodecanol glycidyl ether), difunctional (diglycidyl ester of hexahydrophthalic acid), or higher functionality (e.g. trimethylolpropane triglycidyl ether). These resins typically display low viscosity at room temperature (10-200 mPa.s) and are often used as reactive diluents. As such, they are employed to modify (reduce) the viscosity of other epoxy resins. This has led to the term ‘modified epoxy resin’ to denote those containing viscosity-lowering reactive diluents. However, they are also used without other epoxide ingredients along with anhydride curing agents such as hexahydrophthalic anhydride to make molded objects such as high voltage insulators. This is in fact the main use of the diglycidyl esters.
The cycloaliphatic epoxides contain one or more cycloaliphatic rings in the molecule to which the oxirane ring is fused (e.g. 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate). They are formed by the reaction of cyclo-olefins with a peracid, such as peracetic acid.[3] This class also displays low viscosity at room temperature, but offers significantly higher temperature resistance and correspondingly better electrical properties at high temperatures to cured resins than the glycidyl aliphatic epoxy resins. Another advantage is the complete absence of chlorine, since no epichlorohydrin is used in the manufacturing process. This is particularly useful for electronic applications such as the encapsulation of light emitting diodes. However, room temperature reactivity is rather low compared to other classes of epoxy resin, and high temperature curing using suitable accelerators is normally required.
Glycidylamine epoxy resin
Glycidylamine epoxy resins are higher functionality epoxies which are formed when aromatic amines are reacted with epichlorohydrin. Important industrial grades are triglycidyl-p-aminophenol (functionality 3) and N,N,N,N-tetraglycidyl-4,4-methylenebis benzylamine (functionality 4). The resins are low to medium viscosity at room temperature, which makes them easier to process than EPN or ECN resins. This coupled with high reactivity, plus high temperature resistance and mechanical properties of the resulting cured network make them important materials for aerospace composite applications.Curing epoxy resins
In general, uncured epoxy resins have only poor mechanical, chemical and heat resistance properties. However, good properties are obtained by reacting the linear epoxy resin with suitable curatives to form three-dimensional cross-linked thermoset structures. This process is commonly referred to as curing. Curing of epoxy resins is an exothermic reaction and in some cases produces sufficient heat to cause thermal degradation if not controlled.Curing may be achieved by reacting an epoxy with itself (homopolymerisation) or by forming a copolymer with polyfunctional curatives or hardeners. In principle, any molecule containing a reactive hydrogen may react with the epoxide groups of the epoxy resin. Common classes of hardeners for epoxy resins include amines, acids, acid anhydrides, phenols, alcohols and thiols. Relative reactivity (lowest first) is approximately in the order: phenol < anhydride < aromatic amine < cycloaliphatic amine < aliphatic amine < thiol.
Whilst some epoxy resin/ hardener combinations will cure at ambient temperature, many require heat, with temperatures up to 150°C being common, and up to 200°C for some specialist systems. Insufficient heat during cure will result in a network with incomplete polymerisation, and thus reduced mechanical, chemical and heat resistance. Cure temperature should typically attain the glass transition temperature (Tg) of the fully cured network in order to achieve maximum properties. Temperature is sometimes increased in a step-wise fashion to control the rate of curing and prevent excessive heat build-up from the exothermic reaction.
Hardeners which show only low or limited reactivity at ambient temperature, but which react with epoxy resins at elevated temperature are referred to as latent hardeners. When using latent hardeners, the epoxy resin and hardener may be mixed and stored for some time prior to use, which is advantageous for many industrial processes. Very latent hardeners enable one-component (1K) products to be produced, whereby the resin and hardener are supplied pre-mixed to the end user and only require heat to initiate curing. One-component products generally have shorter shelf-lives than standard 2-component systems, and products may require cooled storage and transport.
The epoxy curing reaction may be accelerated by addition of small quantities of accelerators. Tertiary amines, carboxylic acids and alcohols (especially phenols) are effective accelerators. Bisphenol A is a highly effective and widely used accelerator, but is now increasingly replaced due to health concerns with this substance.
Homopolymerisation
Epoxy resin may be reacted with itself in the presence of an anionic catalyst (a Lewis base such as tertiary amines or imidazoles) or a cationic catalyst (a Lewis acid such as a boron trifluoride complex) to form a cured network. This process is known as catalytic homopolymerisation. The resulting network contains only ether bridges, and exhibits high thermal and chemical resistance, but is brittle and often requires elevated temperature to effect curing, so finds only niche applications industrially. Epoxy homopolymerisation is often used when there is a requirement for UV curing, since cationic UV catalysts may be employed (e.g. for UV coatings).Amines
Anhydrides
Epoxy resins may be cured with cyclic anhydrides at elevated temperatures. Reaction occurs only after opening of the anhydride ring, e.g. by secondary hydroxyl groups in the epoxy resin. A possible side reaction may also occur between the epoxide and hydroxyl groups, but this may be suppressed by addition of tertiary amines. The low viscosity and high latency of anhydride hardeners makes them suitable for processing systems which require addition of mineral fillers prior to curing, e.g. for high voltage electrical insulators.Phenols
Polyphenols, such as bisphenol A or novolacs can react with epoxy resins at elevated temperatures (130-180°C), normally in the presence of a catalyst. The resulting material has ether linkages and displays higher chemical and oxidation resistance than typically obtained by curing with amines or anhydrides. Since many novolacs are solids, this class of hardeners is often employed for powder coatings.Thiols
Also known as mercaptans, thiols with the (S-H) functional group, contain an electron poor hydrogen which reacts very readily with the epoxide group, even at ambient or sub-ambient temperatures. Whilst the resulting network does not typically display high temperature or chemical resistance, the high reactivity of the thiol group makes it useful for applications where heated curing is not possible, or very fast cure is required e.g. for domestic DIY adhesives and chemical rock bolt anchors. Thiols have a characteristic odour, which can be detected in many two-component household adhesives.History
The first commercial attempts to prepare resins from epichlorohydrin were made in 1927 in the United States. Credit for the first synthesis of bisphenol-A-based epoxy resins is shared by Dr. Pierre Castan of Switzerland and Dr. S.O. Greenlee of the United States in 1936. Dr. Castan's work was licensed by Ciba, Ltd. of Switzerland, which went on to become one of the three major epoxy resin producers worldwide. Ciba's epoxy business was spun off and later sold in the late 1990s and is now the Advanced Materials business unit of Huntsman Corporation of the United States. Dr. Greenlee's work was for the firm of Devoe-Reynolds of the United States. Devoe-Reynolds, which was active in the early days of the epoxy resin industry, was sold to Shell Chemical (now Momentive Specialty Chemicals, formerly Hexion, Resolution Polymers and others).Applications
The shelf life of unmixed two-part epoxies is long. There are many anecdotal reports of epoxies mislaid for decades and then used successfully.[4]The applications for epoxy-based materials are extensive and include coatings, adhesives and resin matrices for composite materials such as those using carbon fiber and fiberglass reinforcements (although polyester, vinyl ester, and other thermosetting resins are also used for glass-reinforced plastic). The chemistry of epoxies and the range of commercially available variations allows cure polymers to be produced with a very broad range of properties. In general, epoxies are known for their excellent adhesion, chemical and heat resistance, good-to-excellent mechanical properties and very good electrical insulating properties. Many properties of epoxies can be modified (for example silver-filled epoxies with good electrical conductivity are available, although epoxies are typically electrically insulating). Variations offering high thermal insulation, or thermal conductivity combined with high electrical resistance for electronics applications, are available.[5]
Paints and coatings
Two part epoxy coatings were developed for heavy duty service on metal substrates and use less energy than heat-cured powder coatings. These systems generally use a 4:1 by volume mixing ratio, and dry quickly providing a tough, protective coating with excellent hardness. Their low volatility and water cleanup makes them useful for factory cast iron, cast steel, cast aluminium applications and reduces exposure and flammability issues associated with solvent-borne coatings. They are usually used in industrial and automotive applications since they are more heat resistant than latex-based and alkyd-based paints. Epoxy paints tend to deteriorate, known as chalk out, due to UV exposure.Polyester epoxies are used as powder coatings for washers, driers and other "white goods". Fusion Bonded Epoxy Powder Coatings (FBE) are extensively used for corrosion protection of steel pipes and fittings used in the oil and gas industry, potable water transmission pipelines (steel), and concrete reinforcing rebar. Epoxy coatings are also widely used as primers to improve the adhesion of automotive and marine paints especially on metal surfaces where corrosion (rusting) resistance is important. Metal cans and containers are often coated with epoxy to prevent rusting, especially for foods like tomatoes that are acidic. Epoxy resins are also used for decorative flooring applications such as terrazzo flooring, chip flooring, and colored aggregate flooring. Epoxy flooring has been proven to be an environmentally friendly alternate to other types of flooring, reducing the facility's impact on the environment through less water consumption and less pesticides needed.[6]
Adhesives
Some epoxies are cured by exposure to ultraviolet light. Such epoxies are commonly used in optics, fiber optics, and optoelectronics.
Industrial tooling and composites
Epoxy systems are used in industrial tooling applications to produce molds, master models, laminates, castings, fixtures, and other industrial production aids. This "plastic tooling" replaces metal, wood and other traditional materials, and generally improves the efficiency and either lowers the overall cost or shortens the lead-time for many industrial processes. Epoxies are also used in producing fiber-reinforced or composite parts. They are more expensive than polyester resins and vinyl ester resins, but usually produce stronger and more temperature-resistant composite parts.Electrical systems and electronics
Flexible epoxy resins are used for potting transformers and inductors. By using vacuum impregnation on uncured epoxy, winding-to-winding, winding-to-core, and winding-to-insulator air voids are eliminated. The cured epoxy is an electrical insulator and a much better conductor of heat than air. Transformer and inductor hot spots are greatly reduced, giving the component a stable and longer life than unpotted product.
Epoxy resins are applied using the technology of resin dispensing.
Consumer and marine applications
Epoxies are sold in hardware stores, typically as a pack containing separate resin and hardener, which must be mixed immediately before use. They are also sold in boat shops as repair resins for marine applications. Epoxies typically are not used in the outer layer of a boat because they deteriorate by exposure to UV light. They are often used during boat repair and assembly, and then over-coated with conventional or two-part polyurethane paint or marine-varnishes that provide UV protection.There are two main areas of marine use. Because of the better mechanical properties relative to the more common polyester resins, epoxies are used for commercial manufacture of components where a high strength/weight ratio is required. The second area is that their strength, gap filling properties and excellent adhesion to many materials including timber have created a boom in amateur building projects including aircraft and boats.
Normal gelcoat formulated for use with polyester resins and vinylester resins does not adhere to epoxy surfaces, though epoxy adheres very well if applied to polyester resin surfaces. "Flocoat" that is normally used to coat the interior of polyester fibreglass yachts is also compatible with epoxies.
Epoxy materials tend to harden somewhat more gradually, while polyester materials tend to harden quickly, particularly if a lot of catalyst is used. The chemical reactions in both cases are exothermic. Large quantities of mix will generate their own heat and greatly speed the reaction, so it is usual to mix small amounts which can be used quickly.
While it is common to associate polyester resins and epoxy resins, their properties are sufficiently different that they are properly treated as distinct materials. Polyester resins are typically low strength unless used with a reinforcing material like glass fibre, are relatively brittle unless reinforced, and have low adhesion. Epoxies, by contrast, are inherently strong, somewhat flexible and have excellent adhesion. However, polyester resins are much cheaper.
Epoxy resins typically require a precise mix of two components which form a third chemical. Depending on the properties required, the ratio may be anything from 1:1 or over 10:1, but in every case they must be mixed in exactly the right proportions, and thoroughly to avoid unmixed portions. The final product is then a precise thermo-setting plastic. Until they are mixed the two elements are relatively inert, although the 'hardeners' tend to be more chemically active and should be protected from the atmosphere and moisture. The rate of the reaction can be changed by using different hardeners, which may change the nature of the final product, or by controlling the temperature.
By contrast, polyester resins are usually made available in a 'promoted' form, such that the progress of previously-mixed resins from liquid to solid is already underway, albeit very slowly. The only variable available to the user is to change the rate of this process using a catalyst, often Methyl-Ethyl-Ketone-Peroxide (MEKP), which is very toxic. The presence of the catalyst in the final product actually detracts from the desirable properties; just enough catalyst to harden fast enough is preferable. The rate of cure of polyesters is controlled by the amount and type of catalyst, and the temperature.
As adhesives, epoxies bond in three ways: a) mechanically, because the bonding surfaces are roughened; b) by proximity, because the cured resins are physically so close to the bonding surfaces that they are hard to separate; c) ionically, because the epoxy resins form ionic bonds at an atomic level with the bonding surfaces. This last is substantially the strongest of the three. By contrast, polyester resins can only bond using the first two of these, which greatly reduces their utility as adhesives and in marine repair.
Aerospace applications
In the aerospace industry, epoxy is used as a structural matrix material which is then reinforced by fiber.[8] Typical fiber reinforcements include glass, carbon, Kevlar, and boron. Epoxies are also used as a structural glue; wood and other 'low-tech' materials are glued with epoxy resin. In 1968, Apollo 8's capsule reentered Earth's atmosphere, protected by a heat shield of epoxy resins manufactured by Dow Chemical Company.[9]Biology
Art
Epoxy resin, mixed with pigment, may be used as a painting medium, by pouring layers on top of each other to form a complete picture.[13]Industry
As of 2006, the epoxy industry amounts to more than US$5 billion in North America and about US$15 billion worldwide. The Chinese market has been growing rapidly, and accounts for more than 30% of the total worldwide market. It is made up of approximately 50–100 manufacturers of basic or commodity epoxy resins and hardeners.These commodity epoxy manufacturers mentioned above typically do not sell epoxy resins in a form usable to smaller end users, so there is another group of companies that purchase epoxy raw materials from the major producers and then compounds (blends, modifies, or otherwise customizes) epoxy systems from these raw materials. These companies are known as "formulators". The majority of the epoxy systems sold are produced by these formulators and they comprise over 60% of the dollar value of the epoxy market. There are hundreds of ways that these formulators can modify epoxies—by adding mineral fillers (talc, silica, alumina, etc.), by adding flexibilizers, viscosity reducers, colorants, thickeners, accelerators, adhesion promoters, etc.. These modifications are made to reduce costs, to improve performance, and to improve processing convenience. As a result a typical formulator sells dozens or even thousands of formulations—each tailored to the requirements of a particular application or market.
Impacted by the global economic slump, the epoxy market size declined to $15.8 billion in 2009, almost to the level of 2005. In some regional markets it even decreased nearly 20%. The current epoxy market is experiencing positive growth as the global economy revives. With an annual growth rate of 3.5 - 4% the epoxy market is expected to reach $17.7 billion by 2012 and $21.35 by 2015. Higher growth rate is foreseen thereafter due to stronger demands from epoxy composite market and epoxy adhesive market.[14]
Health risks
The primary risk associated with epoxy use is often related to the hardener component and not to the epoxy resin itself. Amine hardeners in particular are generally corrosive, but may also be classed toxic and/or carcinogenic or mutagenic. Aromatic amines present a particular health hazard (most are known or suspected carcinogens), but their use is now restricted to specific industrial applications, and safer aliphatic or cycloaliphatic amines are commonly employed.Liquid epoxy resins in their uncured state are mostly classed as irritant to the eyes and skin, as well as toxic to aquatic organisms. Solid epoxy resins are generally safer than liquid epoxy resins, and many are classified non-hazardous materials. One particular risk associated with epoxy resins is sensitization. The risk has been shown to be more pronounced in epoxy resins containing low molecular weight epoxy diluents.[15] Exposure to epoxy resins can, over time, induce an allergic reaction. Sensitization generally occurs due to repeated exposure (e.g. through poor working hygiene and/or lack of protective equipment) over a long period of time. Allergic reaction sometimes occurs at a time which is delayed several days from the exposure. Allergic reaction is often visible in the form of dermatitis, particularly in areas where the exposure has been highest (commonly hands and forearms). Epoxy use is a main source of occupational asthma among users of plastics.[16] Bisphenol A, which is used to manufacture a common class of epoxy resins, is a known endocrine disruptor.
Accidents
The Big Dig ceiling collapse, which occurred on July 10, 2006, is an accident which was caused by the use of fast-set epoxy which had a higher rate of creep than standard-set epoxy.The accident resulted in one fatality and cost $54 million to redesign, repair, and inspect all of the tunnels in the D Street connector.
The cost of the fast-set epoxy used to secure the bolts was $1,287.60
