Injection Moulding Machine for Pen Caps
Pen caps come off horizontal injection moulding machines running multi-cavity moulds, often in PP, with PS or ABS for rigid caps. Cavity count and shot weight set the machine size, and cap depth sets the opening stroke. Shrinkage control matters most, because it decides the interference fit on the barrel.
Machine selection for pen caps centres on repeatable fill in every cavity, so cap fit and clip strength stay the same from one cavity to the next. Pratishna Engineers supplies horizontal and hybrid injection moulding machines for pen cap production and can recommend a configuration for your cap and mould.
Moulding Pen Caps?
Share your cap and barrel drawings, material, cavity count and output target, and Pratishna Engineers will recommend a suitable machine.
Machine Requirements for Pen Cap Moulding
A pen cap combines a deep blind bore, a flexing clip and a moulded vent hole in one small part. Points to check when selecting a machine:
- Repeatable shrinkage for a consistent interference fit on the barrel
- PP clip that flexes repeatedly without cracking at the root
- Vent hole moulded in by a core pin, not drilled
- Opening stroke for deep caps on long cores
- Stripper or sleeve ejection for a clean cap mouth
- Cavity balance across a high-cavity hot runner mould
Recommended Machine for Pen Caps
Pen caps are small, so the full mould decides the size. The Hybrid PH Series (120-140 T) suits multi-cavity cap moulds where steady electric injection helps hold the fit. Smaller tools may sit in the E Series (75-180 T), and larger high-cavity tools may need the C Series (140-320 T), with the H Series (120-350 T) for the biggest moulds.
Not Sure Which Machine You Need?
Send your cap, barrel and mould details 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
Answers to the questions cap buyers raise most often.
Which Injection Moulding Machine Is Used to Make Pen Caps?
Cap moulds run on horizontal machines chosen by cavity count and cap depth. Multi-cavity tools often suit the Hybrid PH or E Series, and the C or H Series take larger tools with more cavities.Why Is PP Used for Pen Caps With a Moulded Clip?
When the clip is part of the cap moulding, it has to flex many times without breaking. PP takes that repeated bending. PS and ABS clips can crack at the root, so rigid caps in those grades often carry a separate metal clip.How Is the Vent Hole in a Pen Cap Made?
Many school and general-purpose pen caps carry a vent hole for safety. It is moulded in by a core pin in the tool, not drilled afterwards. That pin needs cooling and support so the hole does not flash over or close.
Why Do Some Pen Caps Fit Too Tight or Too Loose?
Fit depends on cap shrinkage against the barrel diameter. Changes in mould temperature, holding pressure or resin lot shift the bore size, so a tight cap cracks and a loose one falls off in a pocket.Can Pratishna Recommend a Machine for My Pen Cap?
Yes. Share the cap and barrel drawings or samples, material, part weight, mould size, number of cavities and required output, and Pratishna Engineers will recommend a suitable machine.Does the Machine Suit Other Stationery Parts Too?
Yes. A similar machine can produce pen barrels, marker caps and end plugs, sharpener bodies and ID card holder frames, depending on mould size and shot weight.
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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