Injection Moulding Machine for Contactor and Relay Housings and Coil Bobbins
Contactor and relay housings and coil bobbins are made on horizontal injection moulding machines, often in multi-cavity moulds, from glass-filled PA66, glass-filled PBT or PA46 and PPA. Machine size depends on housing area, cavity count and glass-filled shot weight. Flash-free winding surfaces on the bobbin matter most, since flash chafes the coil wire.
Selection for these parts focuses on a wear-resistant screw and barrel for glass-filled grades, hot mould temperature control and clean parting lines. Pratishna Engineers supplies horizontal injection moulding machines for contactor, relay and bobbin parts and can recommend a configuration.
Moulding Relay Housings and Bobbins?
Share your housing and bobbin drawings, grades and cavity count, and Pratishna Engineers will recommend a machine.
Machine Requirements for Contactor, Relay and Bobbin Moulding
Relay and contactor parts sit next to a hot coil and switching contacts, so the machine and process must handle:
- Bimetallic screw and barrel for glass-filled PA66 and PBT
- Flash-free bobbin winding faces and flange edges
- High mould temperatures for PA46 and PPA grades
- Drying of nylon and PBT to avoid brittle thin flanges
- Housing slots and guides held to size for armature travel
- Arc-facing parts in thermoset or high-temperature polyamide
Recommended Machine for Contactor and Relay Housings and Bobbins
Bobbins and small relay housings run in multi-cavity moulds on the E Series (75-180 T). Larger contactor housings, covers and higher-cavity bobbin tools move to the C Series (140-320 T). Arc-facing parts in DMC or BMC need Special Purpose Injection Moulding Machines, built to application by Pratishna Engineers, since the standard series do not run thermoset.
Not Sure Which Machine You Need?
Share your part list and grades so each part can be matched to a machine.
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 KBElectrical & Electronics Components & Machine Guide
A guide to Electrical & Electronics components, covering switches, sockets, MCB and RCCB housings, plug tops, meter boxes, solar connectors and electronic housings. It explains flame-retardant and glass-filled grades, thermoset parts, dimensional control, and how to match each part to a suitable machine.
Download PDFPDF · 202 KB
FAQs / Buyer Questions
Common questions from switchgear and relay makers.
Which Injection Moulding Machine Is Used to Make Contactor and Relay Housings?
Thermoplastic bobbins and relay housings usually run on the E Series, and larger contactor housings on the C Series. Thermoset DMC or BMC parts near the contacts need a special purpose machine.Why Is Heat Ageing Important for Coil Bobbins?
A bobbin sits against a hot coil for its whole service life. The grade must keep strength and insulation after long heat exposure, so the long-term heat rating matters as much as the initial flame rating.Why Must Bobbin Winding Surfaces Be Flash-Free?
Flash on a flange edge or winding face cuts into the enamelled wire as it is wound, causing shorts or open coils. Sharp parting lines, good venting and correct clamp force keep these faces clean.
Are Terminal Pins Moulded Into the Bobbin?
Terminal pins are often pressed into moulded holes after moulding. Some designs mould the pins in as inserts, which needs pin loading and a mould review before a machine is chosen.Can Pratishna Recommend a Machine for My Relay Housing or Bobbin?
Yes. Share the housing and bobbin drawings, grades, cavities, mould dimensions, any inserts and monthly volume, and Pratishna Engineers will suggest standard or special purpose machines.Does the Machine Suit Other Switchgear Parts Too?
Yes. Similar machines can mould MCB housings, RCCB housings, circuit protection components and modular switch parts, subject to the mould and grade.
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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