Thermoplastic
Injection
Moulding

What We Do

Through measured investment and continuous improvement we provide a comprehensive on-site plastic mould shop delivering low to medium volume production runs. We use cutting edge moulding machines to offer a high quality thermoplastic moulding service. Our moulding technicians keep up with modern plastic processing techniques through training and are focused on process optimisation on every production run and trial. We have provided a technical moulding service to industry since we were established in 1972 and support our customers with our combined wealth of knowledge.

We are experienced in processing all high engineering grades of thermoplastics, including LDPE, HDPE, PEEK, TPE, NYLONS to name a few.  Glass filled, UV Stabilised and Flame retardant materials are also material specifications that we are widely experienced in processing.
We use 12 Injection Mould press which range from 22-280 tonne locking power with maximum shot weight of 450 grams and a range of modern ancillary equipment including , material dryers and conveyors. Customer parts are manufactured on horizontal moulding presses with computerised control and a dedicated process monitoring system. This is linked to the ERP System for greater control and traceability.

Our thermoplastic moulding division operates across a two shift pattern allowing production capacity from 7am to 11pm 5 days a week. The division also supports fully auto running production and operator run jobs for part removal or over-moulding applications.

The ERP supply chain system provides full visibility throughout the thermoplastic injection moulding and overall production process, with fully detailed bills of materials and routing operations for each individual component. A contract review is performed on all new purchase orders and the production process is controlled through inspection monitoring with dedicated quality plans for each part in the scope of our accredited quality management system.

Injection Moulding

When it comes to thermoplastic injection moulding we have years of experience and we have worked on a huge range of project types. Please get in touch to discuss your requirements today.

What are the key factors of a product trial?

• A wealth of technical experience
• Mould tooling and production on one site
• ISO9001 accreditation
• Mould trials supported by documented first article inspection
• Quality monitored from first off to final release
• All prime grades of thermoplastics processed
• Experienced with engineering materials
• Tool preventative maintenance program between runs
• Contract review on receipt of order

What industries are we strongest in?

• Medical
• Aviation
• Aerospace
• Electronics
• Marine
• Security

Our experience in high engineering thermoplastic injection moulding, including filled and unfilled grades means we can advice and support both material selection and processing in production. The range of moulding machines has been purposely stepped closely in size. This is so we can provide you with the best possible service on delivery through flexibility in production scheduling. We work with our customers to establish the best ordering a patterns be it  made to order, scheduled call offs or bespoke Kanban agreements.

If you are looking for thermoplastic injection moulding then get in touch today to discuss your requirements.

Why choose Injection Moulding?

There a few key reasons why injection moulding your component may be the best solution as detailed below:

Part Detail

Thermoplastic injection moulded parts can be highly detailed to perform specific tasks required. Ideally the shape required would be created in the mould tool to maximise efficiency and cost especially for medium to high volume production. Alternatively for low volume production component detail can be added as a post production operation to reduce initial start up cost.

Flexibility

The injection moulding process can provide a flexible solution whether the volumes are in the 10’s or the 1,000,000’s.

By carefully considering the annual usage and life expectancy we can design and manufacture suitable tooling to meet your demand.

Fast Production

Injection moulding is a process that can produce the simplest to the most complex parts providing volume production in a short cycle time. Machined parts that would take hours to manufacture can be produced in seconds.

Repeatability

Parts are produced from mould tools that do not change from shot to shot or run to run. This provides excellent repeatability during the production process.

To support this it is essential that we provide consistent process control and traceability at every stage.

Material Choice

One of the biggest advantages of thermoplastic injection moulding is the ability to sample various material types at the development stage.

Thermoplastics can have many different additives to meet specific application such as flame retardancy, UV stabiliser, glass fill or biocompatibility amongst many other options. This will ensure the product meets the specification and is fit for purpose.

Material Types?

Detailed below are a few more widely used materials and why they might be selected:

Material Name
Abbreviation
Properties
Applications
Acetal
POM
Strong, rigid, excellent fatigue resistance, excellent creep resistance, chemical resistance, moisture resistance, naturally opaque white, low/medium cost
Bearings,cams, gears, handles, plumbing components, rollers, rotors, slide guides,valves
Acrylonitrile  Butadiene Styrene
ABS
Strong, flexible, low mould shrinkage (tight tolerances) chemical resistance, electroplating capability, naturally opaque, low/medium cost
Automotive (consoles, panels, trim, vents) boxes, gauges, housings, inhalers, toys
Polyamide 6 (Nylon)
PA6
High strength, fatigue resistant, chemical resistant, low creep, low friction, almost opaque/white, medium/high cost
Bearings, bushings, gears, rollers, wheels
Polycarbonate
PC
Very tough, temperature resistance, dimensional stability, transparent, high cost
Automotive (panels, lenses, consoles) bottles, containers, housings, light covers, reflectors, safety helmets and shields
Polyetheretherketone
PEEK
Strong, thermal stability, chemical resistance, abrasion resistance, low moisture absorption
Aircraft components, electrical connectors, pump impellers, seals
Polyethylene – Low Density
LDPE
Lightweight, tough and flexible, excellent chemical resistance, natural waxy appearance, low cost
Kitchenware, housings, covers and containers
Polypropylene
PP
Lightweight, heat resistance, high chemical resistance, scratch resistance, natural waxy appearance, tough and stiff, low cost
Automotive (bumpers, covers, trim) bottles, caps, crates, handles, housings

Design Considerations

The product design is a key process as the part has to function effectively but it must be designed in a way that allows it to be injection moulded. A few key pointers are listed below: -

Uniformed Wall Thickness

A consistent wall thickness is essential where possible. As the plastic solidifies in the mould it freezes from the outside toward the inside and this can create varying shrinkage rates especially in thick sections. This can be seen in the moulded part by way of sink marks on the outer surfaces, warpage and distortion or through creating stresses due to the contraction of the parts.

Coring Out

Plastic moulded parts which have thick sections can be subject to excess shrink, sink, internal bubbles, voids and poor cosmetics. This is due to the fact that plastic shrinks as it cools from the molten injected state to solid room temperature parts.

Coring out is a technique where material is removed from a part leaving uniform walls and sometimes ribs which provide enough strength and mating surfaces for other parts in the assembly. Coring out is necessary to make the part mouldable and also saves cost and weight.

Surface Finish

Surface finish on a plastic part can serve many functions be it cosmetic or functional. Textures and lettering can be moulded on the surfaces as an aesthetic aid or for incorporating identifying information for end users. Texturing also helps hide surface defects such as knit lines and other surface imperfections. The level of finish can be limited by other factors and extra draft needs to be incorporated to allow for withdrawal of the part from the mould without damaging the surface.

Draft Angles

It is essential to be aware of drafting at the early design stage. Draft angles are generally required on side walls to allow the part to be extracted from the tool without dragging against the tool surface. The minimum would be 0.25˚ for a polished surface.

Draft for texturing is somewhat dependant on the mould design and the specific texture requirement. As a general guideline, 1.5˚ minimum per 0.025mm depth of texture needs to be allowed for if  fine texture is applied. More draft may be needed for heavier textures up to 7.5˚.

Surface Texture

The following information has been collated to provide a guide to the surface finishes that we can achieve through polishing or electrical discharge machining (EDM).

Paper Finish
Pattern
Average Depth
Draft
SPI B-1.600
MT-11001
3um
1"
SPI B-1.600
MT-11002
5um
1"
SPI B-1.600
MT-11003
5um
1"
SPI B-1.600
MT-11004
8um
1"
VDI Finish
Pattern
Average Depth
Draft
VDI 15
MT-11001
25um
2"
VDI 18
MT-11007
38um
3"
VDI 24
MT-11500
13um
1.5"
VDI 28
MT-11010
25um
2.5"
VDI 32
MT-11020
40um
3.5"
VDI 34
MT-11030
50um
5"
VDI 36
MT-11040
75um
6"

Mould Tool Configuration

The injection mould tool can be a complicated and costly capital investment at the outset of a project but it is imperative that the right tool configuration and the specification is right to meet the product demand.

Below are two examples of mould tool configuration: -

Cold Feed

Multi-Cavity Hot Feed

If you are looking for thermoplastic injection moulding then get in touch today to discuss your requirements.

Interested in working with us?
Get in touch today to get started.

If you want to start a project or just have a question, we are always here to help.
Visit our work with us page for estimated tooling costs.