MANUFACTURING · VILHOLI, NASHIK
Rubber Moulding in India: Compound, Mould, Cure, Inspect
How does Margo mould a rubber part?
Margo Rubber Products mixes its own compound, makes its own moulds and produces rubber parts as per your drawing by compression, transfer and injection moulding at one plant in Vilholi, Nashik. Every mixed batch is checked, every run is checked at set-up and every half hour, and every despatch lot is checked for dimensions and hardness before release. Quotation in 48 hours, production in three to four weeks.
01 · PROCESS
The six operations every part goes through
Our PPAP process flow MRP/PF/01 numbers the operations in tens. It was written for one part, an insulator bush, and other parts follow the same sequence.
| Op | Operation | What is checked |
|---|---|---|
| 10 | Raw material receipt | Rubber and SRF carbon black: grade and visual, each lot. Chemicals: brand and shelf life, each lot |
| 20 | Raw material inspection | Material is inspected before it is issued to production |
| 30 | Moulding | Mixing: functional and weight check, every batch. Set-up: 2 pieces dimensionally approved. Run: dimensions every ½ hour, temperature and time every hour |
| 40 | Deflashing and cleaning | Flash removed, parts cleaned |
| 50 | Inspection | ID, OD and thickness, and hardness, each lot |
| 60 | Packing | HDPE bags, labelled cartons; export packing on export lots |
For that bush, MRP/PF/01 sets the mould temperature at 160 ± 10 °C. The figure belongs to that part. Your part gets its own setting on its own control plan.
02 · PROCESS
Custom compound, mixed in-house
Eight compounds are mixed in-house: EPDM, NBR, FKM, silicone, AEM, neoprene, SBR and natural rubber. A trader buys compound pre-mixed. We mix ours and keep the batch record.
Raw rubber, chemicals and SRF carbon black are booked in separately. Every mixed batch gets a functional and weight check, 100 % of batches. The ODR rheometer then runs the cure curve to ISO 6502-2, and the torque and scorch safety from that curve set the press cycle time.
If your drawing calls for a hardness, a temperature range or a fluid we don't already run, the compound is formulated for it. Compound batch, cure parameters and inspection results stay retrievable per production batch.
03 · PROCESS
Mould making and prototypes, in-house
The mould is designed and cut in our own toolroom, from a CAD file, a section drawing or a worn part in an envelope. No outside tool shop sits in the loop, so a revision takes days, not weeks.
- Prototype: 48 to 72 hours from an approved drawing
- Fitment samples: inside two weeks
- Tooling cost: quoted upfront, then amortised into the piece price or credited against committed volume
04 · PROCESS
Moulding: compression, transfer or injection, chosen by the part
Compression moulding. A measured blank goes into the open cavity and the press closes on it. Tooling is simpler and cheaper to cut. It suits thick sections, larger parts and moderate volumes: pads, buffers, mounts, large gaskets.
Transfer moulding. Compound is forced from a pot through sprues into a closed mould. We use it for parts with metal inserts and where the flash has to be tighter than compression gives.
Injection moulding. Compound is injected into a closed, heated mould. Short cycles and repeatable fill suit high-volume small parts.
Rubber-to-metal bonding. Bushes, mounts and bonded seals are bonded in-house. Bond design and failure modes are in our rubber-to-metal bonded parts guide.
Sponge and foam. Moulded sponge and closed-cell foam parts run on the same presses.
Extrusion. Profiles, cords and tubing are made by continuous-cure extrusion, quoted to ISO 3302-1 class E1 to E3.
Presses hold cure temperature and pressure closed-loop. Two pieces are dimensionally approved at set-up before the run starts.
05 · PROCESS
Post-cure and finishing
Programmable electric ovens run post-cure where the compound needs it. Each batch keeps a record of cure time, temperature and pressure that we can pull up later. Flash comes off by cryogenic deflashing or by trimming on variable-speed grinder-cutters.
06 · PROCESS
Inspection and release
First article, then in-process checks through the run, then a final check on every despatch lot before it is released. Sampling follows an AQL table based on IS 2500.
| Test | Standard |
|---|---|
| Hardness, Shore A durometer | ASTM D2240 |
| Tensile strength and elongation | ASTM D412 · ISO 37 |
| Compression set | ASTM D395 · ISO 815-1 |
| Cure curve, ODR rheometer | ISO 6502-2 |
| Heat ageing, hot-air oven to 200 °C | ASTM D573 · ISO 188 |
| Specific gravity | ASTM D297 · ISO 2781 |
| Dimensions, verniers and micrometers to ±0.01 mm | ISO 3302-1 |
Ozone, abrasion, tear, rebound, low-temperature brittleness, fluid immersion and flammability tests go to NABL-accredited partner laboratories on request. Supplier calibration certificates are reviewed against a 13-point checklist. APQP and PPAP where your programme requires them.
07 · PROCESS
Lead times and minimum order
| Stage | Time |
|---|---|
| Quotation and feasibility report | 48 hours |
| Prototype, from an approved drawing | 48 to 72 hours |
| Production, existing tooling | 3 to 4 weeks ex-works Nashik; 2 weeks express where capacity is confirmed |
| New tooling | 3 to 4 weeks plus tooling time |
Minimum run is 10,000 pieces per part number, per compound. Prototype and first-article lots sit outside the minimum and are quoted separately. Installed capacity is five million components a month.
08 · PROCESS
What the certificate covers
ISO 9001:2015, certificate 09111526A, Integral Certification Ltd, valid to 21 February 2027. Scope: rubber moulded components. The scope extension to the extruded and cellular lines is in hand. IATF 16949 is not held; the upgrade is in progress.
09 · PROCESS
Send a drawing
Send the drawing or a sample, the compound or the service conditions (medium, temperature, pressure) and the annual volume. You get a quotation and feasibility report within 48 hours.