FAQ: Compression Moulds, Mould Repair and Die Casting

A compression mould is a two-part steel tool, mounted between the heated platens of a hydraulic press, that shapes thermoset material. The charge is placed in the lower half (the cavity), the upper half (the force) closes on it, and heat and pressure cure the material into the finished part.

We build compression moulds for SMC, DMC, BMC, Bakelite (phenolic), melamine and urea-formaldehyde. Each material needs a different steel, finish, shear edge and heating layout, which we settle in the DFM review.

A typical compression mould takes 6 to 8 weeks from design approval to trial. Large or multi-cavity moulds can take longer; we commit to a date in the quotation and send progress updates.

The price depends on part size, number of cavities, the material, the steel, finish and features such as side cores or engraving. Send your 3D model or drawing with the material and annual volume, and we will send a DFM review and a firm quotation.

Cores, cavities and inserts are usually made in hardened H13 or Böhler W302 ESR for abrasive, glass-filled compounds, with P20 for plates and holders. Cavities are polished and hard chromed where the material needs it.

Yes. Every mould is trialled and the first-off parts are sent for your approval before handover. Our moulds are trialled on presses up to 400 tonnes.

Yes. We repair worn shear edges, re-polish and re-chrome cavities, correct flash and fill problems, and modify moulds for design changes, including moulds made by other tool rooms.

Yes. We sign an NDA on request before you share full details, and we never show customer names or part data in our marketing.

Yes. We quote for buyers outside India and can work to your press details, standards and packing requirements.

SMC stands for Sheet Moulding Compound (sheet molding compound in US spelling). It is a ready-to-mould sheet of polyester resin, chopped glass fibre and mineral filler that is cut, stacked and compression moulded into rigid, flame-retardant parts. An SMC box is simply a box or enclosure moulded from this material.

An SMC mould is a hardened steel compression mould, with a heated core and cavity, that shapes SMC sheet into a finished part under a hydraulic press. It needs a tight shear edge, a polished, wear-resistant cavity and even heating, because SMC is an abrasive glass-fibre compound that flows a long way and cures fast.

They overlap. GRP (glass reinforced plastic) and FRP (fibre reinforced plastic) describe the family of glass-fibre composites; SMC is one way of making them, by compression moulding sheet compound in a steel mould. Most moulded GRP and FRP electrical enclosures, junction boxes and meter boxes are made from SMC.

We build SMC moulds for junction boxes, energy meter boxes, distribution box and MCB enclosures, enclosure bases and lids, covers, and GRP electrical enclosures and kiosk parts, in single and multi-cavity versions.

Cores and cavities are usually machined from H13 or Böhler W302 ESR, hardened for wear resistance against glass fibre, then polished and hard chromed where needed. Plates and holders are made in P20.

Multiply the projected area of the part in cm² by the moulding pressure, typically 40 to 100 kgf/cm² for SMC, and divide by 1000 to get tonnes. We check this in the DFM for every part so the mould matches your press. Our moulds are trialled on presses up to 400 tonnes.

Yes. SMC moulds can hold brass threaded inserts, metal earthing points and engraved logos, ratings and text. We plan insert pockets, locating pins and engraving depth in the DFM so they mould cleanly every shot.

A typical SMC mould takes 6 to 8 weeks from design approval to trial. Large or multi-cavity enclosure moulds can take longer; we commit to a date in the quotation.

Yes. We quote for GRP and SMC enclosure makers in the UK, the Middle East and elsewhere, and work to your press details, standards and packing requirements.

DMC (dough moulding compound) and BMC (bulk moulding compound) are essentially the same material: polyester resin with short chopped glass fibre and mineral filler, supplied as a dough. DMC is the usual name in India and the UK, BMC in the US.

Cavities and cores are usually hardened H13 or Böhler W302 ESR, polished and hard chromed where the material needs it, with P20 for plates and holders.

Both are good insulators. DMC and BMC give higher strength, better arc and track resistance and colour options; phenolic gives very good heat resistance at low cost. We help you choose in the DFM based on the part, standard and volume.

Typically 6 to 8 weeks from design approval to trial. Large multi-cavity moulds can take longer; we commit to a date in the quotation.

Yes. Most of the 100+ dies we have maintained and modified were built elsewhere. We repair and modify high pressure (HPDC/PDC) and gravity (GDC) dies, and are now taking low pressure (LPDC) work.

Yes. Send the old insert, a drawing or a 3D model. We machine new inserts from hot-work die steel such as H13 or Böhler W302, harden and finish them, and fit them to your die.

We are starting with core and cavity sets and our first complete die projects, beginning with low pressure die casting. If you are planning a new aluminium die, contact us early and we will tell you honestly what we can take on.

It depends on the damage. After inspection we send a findings list with a quote and a firm date. Small repairs and polishing are quick; new inserts take longer because of machining and hardening.

Flash, soldering, heat-check marks, drag marks, gas porosity and cold shuts from poor venting, and dimensional drift from worn cores and pins are often caused by the die and are fixed by repairing or modifying it.

Our tool room is in MIDC Ahilyanagar, Maharashtra, within reach of die casters in Pune, Chakan, Aurangabad and Nashik.

Yes. Our team has worked on more than 1,000 moulds, and most of the moulds and dies we repair were built elsewhere. If there is no drawing, we work from the mould and a sample part.

Thermoset compression moulds for SMC, DMC, BMC, Bakelite, melamine and UF, and aluminium die casting dies for high pressure, gravity and low pressure casting.

It depends on the damage. Send photos first; after inspection we give a findings list with a quote and a firm date. Polishing and small repairs are quick; new inserts take longer.

Repair is usually far cheaper and faster when the bolster and most inserts are sound. If wear is widespread or the design has changed a lot, we will tell you honestly when a new mould or new inserts make more sense.

Yes. We add or change ribs, bosses, logos, inserts and wall sections, and can change the parting line or ejection, as long as the steel allows it. We check the change in a DFM review first.

Yes. Every job goes back with a report of what we found, what we did and what to watch at the next maintenance.