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Injection mould making in Delhi, India: designed, built and proven under one roof
General Plastic Industries LLP (GPI) makes plastic injection moulds in its own tool room in Delhi. We have done this since 1968. We build each mould in strong tool steel. Then we test it on our own 15 moulding machines, from 80 to 700 tons. You get good parts from day one.
ISO 9001:2015ISO 45001:2018RoHS compliantScientific Moulding
58+years of mould making (since 1968)
15moulding machines in our own plant
700 Tbiggest machine; the smallest is 80 tons
13+big brands served, like Honda and Maruti Suzuki
Why buyers choose GPI as their injection mould maker
Most delays happen when one firm makes the mould and another firm runs it. At GPI, one team does both. We design the mould, cut the steel, test it and make your parts. Call it a mould or a mold, it stays with one team from start to end.
One partner, start to finish
Design, machining, tests, parts and assembly all happen in one place. Issues get fixed in days.
Proven before production
We test every mould on our own machines, such as Toshiba, L&T and Windsor. We use Scientific Moulding to set each one up right.
Trusted by OEMs
We work for Honda, Maruti Suzuki, Mahle, Uno Minda, Exide, Tata, Royal Enfield, Exicom, Sujata, Bidso, Lumax, Petrochem and Euronics.
Mould making capability at a glance
Here is what we have in one Delhi plant to design, build, test and care for your mould.
| Tool room | Our own CAD/CAM design and CNC machines in Delhi |
|---|---|
| Mould types | Single and multi-cavity, hot runner, 2-plate, 3-plate, family, stack, insert, overmould and thin-wall moulds. Sliders and lifters for side holes and clips. |
| Core and cavity steels | P-20, Stavax, Orvar Supreme / H-13 |
| Mould base steel | C40 / C45 |
| Trial and production presses | 15 machines from 80 to 700 tons: Super Master, Electronica, Toshiba, L&T, Windsor, JIT-D and Nepco |
| Process control | Scientific Moulding for tests and for daily runs |
| Lead time | About 2 months for most moulds. Big or complex moulds take longer. We fix the date in your quote. |
| Certifications | ISO 9001:2015, ISO 45001:2018, RoHS compliant |
| Mould maintenance | For our moulds and for moulds you send us, for as long as they run |
We confirm the number of cavities, mould size and mould life in your quote.
How an injection mould works
An injection mould (or mold) is a steel block in two halves. The machine clamps the halves shut. Hot plastic flows in through the sprue and the runner. It then passes a small hole, the gate, and fills the cavity. The cavity has the shape of your part. The two halves meet at the parting line.
Cold water runs through holes in the steel. This cools the plastic fast and evenly. When the part is hard, the mould opens and pins push it out. Sliders move to the side to free clips and side holes. We plan all of this on screen first. A change on screen is free. A change in steel is not.
Types of injection moulds we make
We help you pick the right type. Big parts and small runs suit one cavity. Large runs pay back more cavities or a hot runner. Parts that go together can share one family mould.
Single-cavity moulds
One part per shot. Best for big parts and small runs.
Multi-cavity moulds
Many parts per shot, all the same size. Guide
Hot runner moulds
Less waste and faster cycles for large runs. Learn more
2-plate and 3-plate moulds
We pick the build that gives the best gate spot and easy upkeep. 2-plate · 3-plate
Family and stack moulds
Sliders and lifters
Moving parts that form side holes, clips and snap fits.
Insert and overmoulds
Moulds that hold brass or metal inserts, or add a soft TPE grip. Inserts
Thin-wall moulds
Fast fill and strong cooling for thin covers and housings.
Mould steels we use, and why
The right steel makes a mould last. It also keeps a good shine and stands up to tough plastics. We pick the steel for each part. We do not use one steel for all.
| Steel | Used for | Key property | Best for |
|---|---|---|---|
| P-20 | Core and cavity | Ready-hardened, easy to cut and polish | Most moulds and medium runs |
| Stavax | Core and cavity | Stainless, does not rust, takes a high shine | Clear or glossy parts, and plastics that harm plain steel |
| Orvar Supreme / H-13 | Core and cavity | Hard steel that resists wear | Long runs and glass-filled plastics like PA 66 GF, PBT GF and PPS |
| C40 / C45 | Mould base | Strong, stable and low cost | The frame and plates that hold the inserts |
Mould life depends on the steel, the plastic, the cavities and good care. We state the life of your mould in the quote.
Choosing steel from the plastic
The plastic you use is the main thing. Glass-filled plastics like PA 66 GF wear steel like sandpaper. So we use hard H-13 steel for them. Some plastics give off gas that can rust plain steel. Stainless Stavax is best here. Clear and glossy parts need a high shine, so Stavax again. For most other parts, P-20 gives good value and long life. We can also put hard steel only where wear is high. That way you pay for top steel only where you need it.
Plastics our moulds are built to run
PPSPESPA 4.6PA 66PA 6
PBTPOMPC and alloysTPUTPEGlass-filled grades
Gating: where the plastic enters the part
The gate is where plastic enters the part. It sets how the part fills and where lines form. It also sets how much the part bends and where a small mark is left. A gate in the wrong spot can leave gaps, dents or weak lines. So we choose it at design and check it at the first test.
| Gate type | Typical use |
|---|---|
| Edge gate | Simple and low cost. Sits on the parting line. Good for flat parts where a small edge mark is fine. |
| Submarine (tunnel) gate | Breaks off by itself when the part comes out. Good for small parts in multi-cavity moulds. |
| Pin-point gate (3-plate) | Feeds the top face of the part. Leaves a tiny mark. The runner falls away by itself. |
| Hot runner gate | Feeds hot plastic straight into the part. Almost no waste. Best for large runs. |
| Fan gate | Spreads the flow wide. Cuts bending and flow marks on flat parts. |
| Diaphragm gate | Fills round parts from the centre. No weld lines. |
- Runner / gate
- Moulded part
- Gate position
- Parting line
- Heated nozzle
Cooling and cycle time
Cooling takes the most time in each cycle. So good cooling makes every part cheaper. Water lines close to the cavity take heat out evenly. The cycle gets shorter and parts stay flat. Poor cooling does the reverse. One side shrinks more and the part bends. We plan the water lines with the cavity. We add baffles in deep cores. Then we check the heat at the first test. Read more on cooling rate in injection molding and how to reduce cycle times.
How our injection mould making process works
Six clear steps take you from your CAD file to a ready mould. You approve each step.
- 1
Enquiry and part review
You send a 3D model and a drawing. We check the walls, angles and gates. We suggest small changes that make the part easy to mould. See what to prepare for a mold quote.
- 2
Quotation
We tell you the mould type, cavities, steel, time and mould life. You know just what you are buying.
- 3
Mould design on CAD/CAM
We draw the full mould on screen. You approve it before we cut steel. Read why mould design matters.
- 4
CNC machining in our tool room
We cut the core, cavity and base in our own tool room. Then we fit, polish and build the mould.
- 5
Trial and first samples
The first test is called T0. It checks that the mould fills, cools and opens well. We set the machine with Scientific Moulding. We measure the parts against your drawing and fix the steel if needed. Then we send samples for your OK.
- 6
Production and maintenance
Your mould goes into production at GPI, with assembly and contract manufacturing if you need it. We clean, polish and repair moulds, even ones you send us. See our guide to mold maintenance.
Industries we make moulds for
Automotive and two-wheeler
Parts that must fit, seal or carry load, for car and bike makers.
Electrical, lighting and appliances
Housings, covers and parts for electrical, battery, lighting and home brands.
Export and precision work
Moulds and parts for buyers abroad, with clear talk in English.
Mould ownership, storage and maintenance
A mould is a costly asset. So put the terms in writing before work starts. Do this with us or any toolmaker. Moulds that run at GPI get cleaned and checked as part of each run. We also care for moulds you send us.
1
Ownership
Who owns the mould and its design once it is paid for.
2
Storage and insurance
Where the mould is stored and who insures it.
3
Maintenance and changes
Who pays for care, repairs and design changes. Regular cleaning and polish keep parts good and make the mould last.
4
Transfer
How and when the mould can move to another plant.
How to get an injection mould quote from GPI
Send us these six things. We can then quote the mould type, steel, time and price in one go.
1
3D CAD file
A STEP or IGES file, plus a 2D drawing with sizes.
2
Plastic grade
Name the plastic. Say if it has glass fill or fire-safe grade.
3
Annual volume
How many parts you need each year. This sets the cavities and steel.
4
Critical dimensions
Mark the sizes that matter most for fit.
5
Finish and appearance
Gloss, texture, and faces where no marks are allowed.
6
Timing
When you need first samples, and when you need full supply.
Related guides from our blog
Injection mould making: frequently asked questions
Short, clear answers to the questions buyers ask most.
What is injection mould making?
Injection mould making is the work of building the steel tool that shapes plastic parts. A toolmaker designs the mould on CAD, cuts the core and cavity from tool steel, and fits them in a base. The mould is then tested on a machine. GPI has made injection moulds in Delhi since 1968.
How long does it take to make an injection mould?
An injection mould takes about 2 months to make. Simple moulds can be faster. Large or multi-cavity moulds take longer. The time covers design, steel cutting, fitting, polishing and the first test. At GPI, we fix the date in your quote and update you at each step.
How much does an injection mould cost in India?
The cost of an injection mould in India depends on the part size, the number of cavities, the steel and how complex the part is. A hot runner also adds cost but cuts waste. For an exact price, send your 3D file to GPI. We give a free, detailed quote.
Which steel is best for injection moulds?
P-20 steel is best for most injection moulds. It is ready-hardened, easy to cut and gives long life. H-13 is best for glass-filled plastics and long runs, as it resists wear. Stavax is best for clear, glossy or rust-prone work. The base is often C40 or C45 steel.
What is the difference between core and cavity in a mould?
The cavity is the hollow half of a mould that forms the outside of the part. The core is the raised half that forms the inside. The two halves meet at the parting line. Plastic fills the gap between them and sets into the shape of your part.
What is the difference between a mould and a die?
A mould shapes melted plastic. A die cuts or presses metal, or shapes extruded material. In India, people often use the words for the same thing. For plastic injection work, mould, mold, tool and die all mean the steel tool that shapes the part.
What is a multi-cavity mould?
A multi-cavity mould makes two or more of the same part in one shot. It costs more to build than a single-cavity mould. But it lowers the price of each part on large runs. GPI balances the runners and cooling so every cavity makes the same size part.
What is a hot runner mould?
A hot runner mould keeps the plastic hot all the way to the part. There is little or no runner to throw away. This saves plastic and makes each cycle shorter. Hot runner moulds suit large runs. GPI designs and builds hot runner and cold runner moulds.
How long does an injection mould last?
An injection mould lasts as long as its steel, plastic and care allow. Hard steel like H-13 lasts longer than softer steel. Glass-filled plastics wear a mould faster. Regular cleaning and polish add years of life. GPI states the expected life of your mould in the quote.
Where can I get an injection mould made in Delhi?
You can get an injection mould made at General Plastic Industries in Delhi. Our tool room is at Plot No. 67, Rajasthani Udyog Nagar, near Jahangirpuri Metro, G.T. Karnal Road, Delhi 110033. Call +91-9999 600 619 or email sales@generalplastic.in for a free quote.
Do you test the mould before production?
Yes, GPI tests every mould before production. We run it on our own machines, from 80 to 700 tons. We set it up with Scientific Moulding. Then we measure the parts against your drawing. You approve the samples before full production starts.
Who owns the mould after it is paid for?
Mould ownership should be agreed in writing before work starts. The terms should cover who owns the mould and its design, where it is stored, who pays for care, and how it can move. GPI agrees these points with you at the quote stage.
Ready to build your next injection mould?
Send your 3D model and drawing. We will reply with the mould type, steel, time and price. We are ISO 9001:2015 and ISO 45001:2018 certified and RoHS compliant, and we use Scientific Moulding.