Injection Moulding Machine for Geometry Instruments
Geometry instruments such as set squares, protractors and compass parts are made on horizontal injection moulding machines from crystal PS, PMMA, ABS or POM, often with the set in family moulds. Machine size follows the flat projected area of the set and the cavity layout. Shrinkage matters most, because it sets the accuracy of every angle and scale mark.
Machine selection for geometry sets focuses on even, repeatable shrinkage and flat parts in clear grades. For geometry instrument production, Pratishna Engineers supplies horizontal injection moulding machines and can recommend a configuration for your set and moulds.
Manufacturing Geometry Sets?
Share the instruments in your set, the material and your mould layout, and Pratishna Engineers will suggest a machine.
Machine Requirements for Geometry Instrument Moulding
Set squares and protractors are graduated flat parts, so scale accuracy and flatness come first. The machine should give:
- Repeatable shrinkage that holds angle and scale accuracy
- Even cooling so straight edges stay flat
- Clear PS or PMMA filled without flow lines
- Gate placement away from graduations and drawing edges
- Precise, concentric pivot bore on compass parts
- Shrinkage control on POM compass leg-lock parts
Recommended Machine for Geometry Instruments
Set squares and protractors are thin, flat parts whose size comes from their area, not their weight. Many geometry set and compass tools fit the E Series (75-180 T). Large set squares, long scales or family moulds that carry the full set need more clamping force across the flat area, from the H Series (120-350 T) or C Series (140-320 T).
Not Sure Which Machine You Need?
Send your geometry set drawings and mould layout for a machine recommendation.
Why Choose Pratishna Engineers?
- Application-Based Machine Selection
- In-House Engineering & Manufacturing
- Multiple Machine Series
- Production-Focused Solutions
- End-to-End Technical Support
- Industry-Specific Solutions
- Machine Lifecycle Support
Injection Moulding Machine Buyer Resources
Download practical resources to help you select, size and specify the right machine.
Horizontal Injection Moulding Machine Selection Guide
A step-by-step guide covering the key inputs needed to select the right machine: product weight, projected area, number of cavities, plastic material, required clamping force, shot / injection capacity, mould dimensions, production quantity, cycle time and automation requirement.
Download PDFPDF · 265 KB
How to Calculate Clamping Force for an Injection Moulding Machine
A clear methodology that explains how clamping force is calculated, covering projected area, injection pressure, safety factor, number of cavities and material considerations.
Download PDFPDF · 363 KBStationery Components & Machine Guide
A guide to Stationery components, covering pen barrels, caps, refills, markers, rulers, sharpeners, clips, ID card holders and desk tools. It explains high-cavity hot runner moulds, clear parts, small mechanisms, and how to match each part to a suitable machine.
Download PDFPDF · 204 KB
FAQs / Buyer Questions
Questions geometry box makers often raise with us.
Which Injection Moulding Machine Is Used to Make Geometry Instruments?
Small protractors and compass parts usually run on the E Series. Large set squares and family tools with several instruments in one mould step up to the C or H Series as the total flat area grows.Why Are Geometry Instruments Moulded in Clear Plastic?
A transparent set square or protractor lets the user see the drawing underneath. Crystal PS and PMMA give that clarity but need a polished mould, gating that keeps flow lines off the reading area, and dried PMMA.How Is Angle Accuracy Held on a Moulded Protractor?
Cavities are cut oversize for the shrinkage of the chosen grade, and first-off parts are checked against a reference. Any change in material, mould temperature or holding pressure needs a recheck, since shrinkage moves the scale.
Which Compass Parts Can Be Injection Moulded?
Compass bodies, heads and leg-lock parts can be moulded, with POM used where parts slide or lock. The pivot needs a precise, concentric bore, and some designs use a metal pivot or lock instead.Can Pratishna Recommend a Machine for My Geometry Set?
Yes. Share drawings or samples of each instrument, the materials, mould layout, cavity plan and target output, and Pratishna Engineers will recommend a machine.Does the Machine Suit Other School Stationery Parts Too?
Yes. Machines in this range can also mould plastic rulers, sharpeners, pen caps and ID card holders, depending on the tool.
Technical Disclaimer
Disclaimer: The information provided in this webpage is for general informational and educational purposes only. It is based on technical references and industry information available at the time of preparation and may be subject to change. It does not constitute engineering, technical, commercial or professional advice, nor does it constitute a quotation, specification, warranty or contractual commitment by Pratishna Engineers.
Actual injection moulding machine and process requirements vary according to the component design, material, mould, production volume, machine configuration and operating conditions. The information, examples, calculations and recommendations provided should be independently evaluated and verified for the specific application before making any equipment, process or production decision. Information obtained from third-party sources remains subject to the accuracy and limitations of those sources.
Limitation of Liability: Pratishna Engineers makes no representation or warranty, express or implied, regarding the completeness, accuracy or suitability of the information for any particular application. To the extent permitted by applicable law, Pratishna Engineers shall not be liable for any loss, damage, cost or consequence arising from reliance on or use of the information contained in this webpage. Final machine selection, configuration and application suitability should be confirmed with Pratishna Engineers based on complete and accurate project requirements.
Talk to Our Engineers
Planning a New Injection Moulding Project?
Share your component, material, mould and production target. Our engineering team will help you identify the right machine configuration.
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