A rubber seal or a moulded plastic part can pass a sample check and still fail in the field six months later, because nothing in the order said what the material had to be. With rubber the gap is wider than with most materials: two compounds of the same hardness and colour can behave completely differently in oil, heat or sunlight, and only the factory knows the recipe. Before you send drawings to a Malaysian moulder, decide who owns the formula, how the material is defined on paper, who owns the mould, and what the test report has to prove.
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Match the part to the right kind of Malaysian rubber factory
Malaysia’s rubber industry splits into latex products, tyres and tyre-related products, and industrial and general rubber products, and a moulded seal, hose or mat belongs with the third group, not with a latex dipping plant.
The Malaysian Investment Development Authority (MIDA) describes the industry in exactly these three segments. It lists the industrial and general rubber goods makers as serving the automotive, electrical and electronics, machinery and construction sectors with products such as belting, hoses, seals and sheeting. Latex plants are built around dipping lines for gloves and similar thin products, and their equipment, testing and staff skills do not carry over to compression- or injection-moulded parts.
This matters before you shortlist anyone. A factory that has spent years on one process can quote almost anything, but the process it actually runs every day decides your scrap rate and your consistency. Ask each candidate which moulding methods it runs in house (compression, transfer, injection), whether it mixes its own compound or buys it in, and which of its current products is closest to yours. For how to build the shortlist and check the company in the first place, see sourcing from Malaysia: MATRADE, SSM and SIRIM; this article starts where that one ends.
Checked against MIDA’s published rubber products page on 17 October 2026.
Decide who owns the compound before you ask for a price
Either you specify the performance and let the factory own its recipe, or you supply the recipe and own it yourself, and the order must say which, because the two give you very different rights later.
Most buyers do the first. You state what the rubber must do, the factory develops or picks a compound that meets it, and the recipe stays the factory’s know-how. That is normal and fair, but it has consequences: if you move production later, the new factory has to develop its own compound and you re-qualify from the beginning.
If the part is critical, or you already have a qualified formula from a previous supplier, you can supply the recipe. Then the contract should say that the formula is yours, that it is used only for your parts, and that no ingredient may be substituted without your written approval.
| Route | Who owns the recipe | What you can demand | Risk to manage |
|---|---|---|---|
| Performance specification | The factory | Results against your test list, on every lot | A silent ingredient change that still passes the hardness check |
| Buyer-supplied formula | You | The exact ingredients, their sources and the mixing record | The factory cannot buy an ingredient locally and proposes a substitute |
| Factory catalogue compound | The factory | The data sheet values, if you write them into the order | The data sheet describes a typical lot, not yours |
Whichever route you take, write into the order that the compound is frozen once the samples are approved. A change of polymer grade, filler, plasticiser or curing system then needs your approval first, with fresh test results. Without that clause, a factory may switch to a cheaper ingredient that still passes the one test you check.
Write the material call-out so that it can be tested
A rubber call-out must give the base polymer, the hardness with a tolerance, and a short list of properties, each tied to a named test method and a pass value, because “NBR, 70 Shore A, black” describes a colour more than a material.
For automotive and many industrial parts, buyers often use the ASTM D2000 line call-out system, which codes the heat and oil resistance class, hardness and minimum tensile strength, plus suffix tests for things such as compression set or ozone resistance. If your drawing already carries such a code, keep it. If not, the table below is a practical minimum. The pass values come from your application, not from this article.
| Property | Typical test method | Why it matters |
|---|---|---|
| Hardness | ISO 48-4 (durometer, Shore A) | The figure everyone checks; a tolerance must be stated, e.g. nominal ± a set number of points |
| Tensile strength and elongation at break | ISO 37 | Shows whether the compound is properly mixed and cured |
| Compression set | ISO 815-1 | The property that decides whether a seal still seals after months under load |
| Heat ageing | ISO 188 | Change in hardness and tensile after a set time at temperature |
| Resistance to liquids | ISO 1817 | Swelling in the oil, fuel or chemical the part will actually meet |
| Ozone resistance | ISO 1431-1 | Cracking of parts exposed to outdoor air |
| Dimensional tolerances | ISO 3302-1 | Moulded rubber shrinks and flexes, so metal tolerances cannot be copied onto it |
State the test conditions as well as the method: the temperature, the duration and the test liquid. “Compression set per ISO 815-1” with no time and temperature is not a requirement that anyone can fail.
For moulded plastic parts the same logic applies, but the call-out names a resin grade rather than a recipe. Specify the polymer and grade (or an approved equivalent list), the colour masterbatch and its loading, and whether regrind is allowed and up to what proportion — or ban it. A part moulded from the right resin with too much reground sprue can lose impact strength, and you would not see it on a dimensional check.
💬 Not sure which properties belong on your rubber or plastic part’s drawing? We work through the operating conditions with you and turn them into a call-out that a Malaysian factory can quote and test against. Ask us about your part.
Settle the mould: who pays, who owns, who can move it
If you pay for the mould, the contract should say in writing that you own it, that it is marked as your property, and that the factory must release it to you or your nominee on request.
A mould paid for in full but never described in a contract is, in practice, very hard to recover. Put the following in writing before the mould is cut:
- Ownership and marking. The mould is your property from payment, and carries a plate or engraving with your company name and the tool number.
- Use. The mould is used only for your parts. No parts from it are sold to anyone else.
- Maintenance and life. Who pays for routine maintenance, and who pays when the mould wears out and needs refurbishing or replacing.
- Cavity count and design approval. The number of cavities, the parting line and the gate and vent positions are approved by you, since they affect flash and appearance.
- Release. The steps, notice period and condition in which the mould is handed over if you move production.
- Storage and insurance. Where the mould is kept between orders and who insures it.
Rubber moulds also wear in a way that shows on the part: flash grows, and fine detail softens. Ask for the factory’s own trimming and flash limits, and put the maximum flash you accept on the drawing.
Ask for a test report that proves something about your lot
A useful test report names your part, your compound code and your production batch, shows measured values against your pass limits, and says which laboratory did the test and to which method.
Many reports buyers receive are a material data sheet with a new date on top. That proves nothing about the parts in the container. Ask for the items below and reject a report that lacks them.
| Item on the report | What it proves |
|---|---|
| Part number, drawing revision and compound code | The report relates to your part, not to a similar one |
| Batch or lot number, and date of mixing and moulding | The results belong to the parts being shipped |
| Each property with the test method, test conditions, measured value and your limit | The lot passed your call-out, not just a typical value |
| Name of the laboratory, and whether it is in house or external | Who stands behind the numbers |
| Accreditation of an external laboratory, if you required one | That the method is within the lab’s accredited scope |
| Signature and date of the person who approved release | Someone at the factory took responsibility for the lot |
In Malaysia, laboratory accreditation to ISO/IEC 17025 is given by the Department of Standards Malaysia under its SAMM scheme. The Malaysian Rubber Board (Lembaga Getah Malaysia) also runs rubber testing laboratories. If you require third-party testing, ask for the laboratory’s accreditation number and check that the exact test method is listed in its current scope — accreditation covers named methods, not the whole laboratory.
Agree the testing frequency too: full tests at first-article approval and after any change, a short list (hardness, dimensions, appearance) on every lot, and the longer tests such as compression set or ageing at an agreed interval. Then use staged sample approval and a pre-shipment inspection with an agreed sampling plan — both written for Vietnam, but the method is the same in Malaysia.
Keep the approved part from drifting
Lot traceability and a written change rule are what stop the hundredth shipment from being different from the approved sample.
Ask the factory to mark each carton, and if possible each part or bag, with a lot code that links back to the mixing batch and the moulding date. Keep a set of retained samples from the approved first article at both ends. When a field complaint arrives, the lot code is what lets you tell one bad batch from a design problem.
Write a short change rule into the supply agreement. Any change to the compound, the raw material supplier, the mould, the moulding process or the production site must be notified in advance and approved by you, with new test results. This is the rubber equivalent of a change notice in electronics, and it is the clause most often missing from first orders.
Hand over to export and destination paperwork
Once the part is approved, the remaining steps are the same as for any Malaysian export: confirm whether a certification applies in the destination market, request the right certificate of origin, and confirm the HS code.
Do not reuse an HS code from a different rubber product. Classification of rubber articles depends on the material (vulcanised or not, cellular or not) and on what the article is, so a seal, a hose and a mat may fall under different headings. For SIRIM, the certificate of origin and the ports, see the Malaysia buyer guide. If the parts are going to Japan, the choice of agreement is in ASEAN imports into Japan: EPA or RCEP. Moulded rubber floor mats for cars are covered separately in car accessory OEM in Taiwan, Thailand and Malaysia.
If the same project also needs electronic assemblies, see our note on electronics contract manufacturing in Malaysia. Parts sold into halal-sensitive markets raise their own questions, covered in halal contract manufacturing in Malaysia.
💬 Ready to move a rubber or plastic part to a Malaysian factory, or to add a second source? We handle the brief, the factory check, the sample approval and the shipment as one project. Tell us about the part.
Frequently asked questions
1. Will a Malaysian rubber factory tell me its compound formula?
Usually not, if you ordered against a performance specification — the recipe is the factory’s know-how. You can still require that the compound is frozen after approval and that any change is notified with new test results. If you need to own the formula, supply it yourself and say so in the contract.
2. Is a hardness value enough to specify a rubber part?
No. Hardness is easy to measure but says little about how the rubber behaves in oil, heat or under long compression. Add tensile strength and elongation, compression set, and whichever ageing or fluid tests match the operating conditions, each with a test method and a pass value.
3. Who owns the mould if I pay for it?
Only what the contract says. Write down that the mould is your property, that it is marked with your name, that it is used only for your parts, and how and when it will be released to you.
4. What should a test report from a Malaysian factory contain?
Your part number and drawing revision, the compound code, the batch number, each property with method, conditions, measured value and your limit, the laboratory name and the release signature. A data sheet with typical values is not a test report.
5. Can I use the HS code from my previous rubber product?
Do not assume so. Rubber articles are classified by material and by what the article is, so confirm the code for each new part before you rely on a duty rate or a certificate of origin.
Sources: Malaysian Investment Development Authority (MIDA), rubber products industry page; Department of Standards Malaysia, laboratory accreditation scheme (SAMM); Malaysian Rubber Board (Lembaga Getah Malaysia); ISO 48-4, ISO 37, ISO 815-1, ISO 188, ISO 1817, ISO 1431-1 and ISO 3302-1 (titles and scope); ASTM D2000 classification system for rubber products. Checked on 17 October 2026.