Injection Molding for Home Appliance Parts
Appliance parts have to survive heat, detergent, load and ten years of use while still looking clean on a showroom floor. We mould both ends of that job, structural internals filled with glass fibre and cosmetic panels that cannot show a flow line, and we review the part for both before any steel is cut.
Free Consultation24h
Rapid Quote
100 pcs
Molding MOQ
±0.05 mm
Part Tolerance
4 to 6 weeks
Tooling Lead Time
Materials
| Grade | Properties | Typical Applications |
|---|---|---|
| PP Homopolymer and Copolymer | Low density around 0.90 gram per cubic centimetre, good fatigue resistance for integral hinges, resistant to household detergents and chemicals, homopolymer is stiffer and copolymer absorbs impact better in the cold | Washing machine tub components, dishwasher internals, water tank parts, pump housings, detergent resistant enclosures |
| PP Glass Filled (20 to 30 percent) | Stiffness roughly doubles at 30 percent glass with a useful rise in heat deflection temperature, lower mould shrinkage than unfilled PP, anisotropic shrinkage means warp has to be modelled rather than guessed | Structural brackets, load bearing frames, washing machine tub spiders, fan mounts, replacing metal in wet applications |
| ABS | Good cosmetic finish straight from the tool, takes paint and printing well, dimensionally stable, available in high gloss and matte grades with consistent colour across lots | Cosmetic covers, control panels, exterior housings, bezels, handles and knobs |
| HIPS (High Impact Polystyrene) | Lowest material cost in the appliance family, easily processed with low mould shrinkage around 0.4 to 0.6 percent, adequate toughness for interior parts but poor UV and chemical resistance | Interior housings, drawer bodies, air conditioner housings, refrigerator inner liners and door bins |
| POM (Polyoxymethylene, POM-H and POM-C) | Very low coefficient of friction, excellent wear and fatigue resistance, high stiffness, but high and unequal shrinkage around 1.8 to 2.5 percent that must be accounted for in the cavity | Gears, rollers, cam followers, latch mechanisms, detergent pump components, sliding rails |
| Flame Retardant Grades (for live parts enclosures) | UL 94 V-0, V-2 and 5VA listed resins supplied with the resin maker documentation, available halogen free or brominated, typically at a cost premium and with a narrower processing window | Enclosures around live electrical parts, heater housings, connector blocks, control board surrounds |
Process Parameters
| Parameter | Standard Range |
|---|---|
| Moulding Machine Range | 50 to 800 T |
| Maximum Moulded Part Size | up to 800 x 600 x 400 mm |
| Wall Thickness for Cosmetic Panels | 1.5 to 3.0 mm, uniform across the part |
| Recommended Rib Thickness | 50 to 60 percent of the adjacent wall to avoid sink |
| Draft Angle | 0.5 to 2 degrees per side, more on textured surfaces |
| Melt Temperature Window | 180 to 260 degree C by resin |
| Mould Temperature | 30 to 90 degree C by resin and surface requirement |
| Injection Pressure Available | 500 to 1,300 bar |
| Cycle Time | 15 to 60 seconds depending on part wall and cooling |
| Colour Match | Pantone or RAL reference, delta E under 1.5 against the approved sample |
Surface Finishes
VDI 3400 Texture
Chemically etched cavity texture in defined grades from fine matte to coarse grain. On an appliance panel this hides tool witness marks and fingerprints, which is why almost every visible internal surface is textured rather than polished. The texture depth sets the draft requirement, so the two have to be designed together.
SPI and Diamond Polish
Multi stage polishing to a gloss or semi gloss finish for panels that must read as premium. Polishing is a discipline of its own here, because any mark the eye can find on the cavity becomes a mark the customer finds on the part, so these cavities are inspected under raking light before the first trial shot.
Wet Painting and Soft Touch Coating
Two pack polyurethane or water based coatings applied in a controlled booth, in gloss, matte or soft touch. Paint hides flow lines and gives a consistent colour across parts moulded in different lots, which matters when a replacement panel is shipped years later.
Pad Printing and Laser Marking
Pad printing for logos, symbols and multi colour markings on curved surfaces, and laser ablation for permanent part numbers and date codes that must survive cleaning. Depth and placement are set so the marking stays legible after years of detergent exposure.
Hot Foil and Heat Staking
Metallic foil transfer for brand details and decorative trim, and heat staking for joining the plastic to itself or to a metal insert without a separate fastener. Both keep the assembly count down, which is usually the cheapest assembly saving available in an appliance programme.
Moulded in Colour and Colour Consistency Control
Where painting is not justified, colour is matched in the resin with masterbatch, and continuity is controlled by lot. The realistic outcome is that unpainted panels can show slight variation between lots over a long programme, and we will tell you when that matters enough to switch to paint.
Design for Manufacturing (DFM)
- Keep wall thickness uniform, because variation is what produces sink marks and warp, and the tooling fix for either costs more than the design change
- Size ribs at 50 to 60 percent of the adjacent wall, since a rib sized to look strong on a drawing is the single most common cause of sink on a cosmetic face
- Move the weld line away from the cosmetic face by gate placement, then confirm position with the trial rather than assuming it landed where intended
- Add venting at the last area to fill, because a burn mark from trapped air shows as a brown smudge on a white panel and cannot be cleaned off
- Specify food contact early for anything touching water or food, because it changes the grade available, not just the documentation
- Choose glass filled grades only when stiffness actually governs, since the added stiffness comes with anisotropic shrinkage and more warp to manage
- Design integral hinges in PP with the gate feeding across the hinge rather than along it, which is what gives the hinge its fatigue life
- Ask for a family tool where an appliance has several similar housings, because the cavities share tooling cost across part numbers
- Plan ejection so witness marks fall on hidden faces, since marking is a mechanical necessity and only its placement is negotiable
- Upload STEP, IGES or DXF files and receive a free DFM and material review within 24h, including wall analysis and cavity count options
Tooling & Capacity
| Type | Lead Time | Suitable For |
|---|---|---|
| Aluminium Soft Tooling | 2 to 3 weeks | Pilot runs of 25 to 500 pieces, design freeze batches, market testing and pre production builds |
| Production Steel Tooling | 4 to 6 weeks | Annual volumes above roughly 20,000 pieces, polished or textured cosmetic cavities, hardened inserts where needed |
| Multi-Cavity Tool | 4 to 6 weeks | High volume appliance programmes where cycle time dominates the piece price |
| Family Tool | 5 to 7 weeks | Several near identical housings or brackets sharing one tool with interchangeable inserts |
Quality Assurance
- Resin lot traceability recorded for every production run, with the supplier certificate filed against the batch
- First article inspection with dimensional report on the critical fit interface before any further shots are run
- In process weight checks on a defined interval to catch dosing drift before it becomes a dimensional failure
- Cosmetic inspection of panels under agreed lighting against the approved sample, not against a description
- Fit check against the mating part or assembly fixture at first article and at defined intervals
- Colour measured and recorded against the reference, with delta E reported per production lot
- Weld line and venting review during the trial, with gate or vent corrections made before production release
- Warp check on flat panels measured unclamped, since clamping hides the defect the customer will see
- Each appliance lot ships with a dimensional report and material certificate, plus the Certificate of Origin
- Third-party SGS, Bureau Veritas or TUV inspection is arranged at any stage on request for appliance moulding
Applications
- Washing machine tub supports, dispensers and control housings
- Refrigerator inner liners, door bins, drawers and shelf frames
- Air conditioner housings, vents, grilles and fan components
- Vacuum cleaner bodies, nozzles and dust bin components
- Small appliance housings, handles and covers
- Kitchen appliance internal frames and pump components
- Water dispenser and water tank covers
- Dishwasher internal frames, racks and spray arm parts
- Structural internals replacing metal in wet and detergent exposed locations
Why Choose FHY Precision
Both ends of an appliance programme in one factory, structural glass filled internals and cosmetic exterior panels
Material selected against the actual service conditions, detergent, temperature, load and the relevant safety requirement, rather than from habit
Wall thickness, rib sizing and gate position reviewed before tooling, which removes most sink and weld line issues before they exist
Pilot runs of 25 to 500 pieces from aluminium tooling, so tooling decisions rest on real parts rather than on a drawing
Colour controlled across lots and programmes, with paint offered where consistency over years genuinely requires it
Family tools and multi-cavity options quoted side by side so the tooling route is decided on your annual volume
Resin lot traceability is kept, and SGS, Bureau Veritas or TUV third-party inspection is available on request
Single-source production in China at factory-direct pricing, no trading layer
FAQ
1. Can you mould both the structural internal parts and the cosmetic exterior panels of an appliance?
Yes, and doing both in one factory generally helps. The internal parts drive the material choice towards glass filled grades with higher stiffness, while the exterior panels drive finish and colour. When both sit under one review, the interface between them gets checked before tooling, which is where appliance programmes usually discover their problems.
2. Which materials do you recommend for washing machine and dishwasher internal parts?
Usually a polypropylene answer, either copolymer where impact in the cold matters or glass filled where stiffness governs. PP survives detergent and hot water chemistry in a way most polymers do not, and 30 percent glass gives roughly double the stiffness. We will ask about the operating temperature and the load path before recommending the grade, because those decide it.
3. Do you supply UL 94 V-0 or glow wire capable materials?
Yes. Flame retardant grades listed to UL 94 V-0 or 5VA are standard for anything near a live part, and grades formulated to pass glow wire testing exist for enclosures around heating elements. The listing attaches to the resin grade and we pass through the resin maker documentation for whatever grade we run, so you have the evidence your own compliance file needs rather than an assurance.
4. Can you mould food contact parts for water tanks and dispensers?
Yes, and it should be specified at quote stage because it narrows the grades rather than only adding paperwork. We will ask which market you ship to, since the documentation set differs between regions, and we will confirm the grade is appropriate for the contact type and temperature before quoting.
5. How do you stop sink marks on large cosmetic panels?
By designing them out rather than by holding process harder. Sink comes from thick sections cooling slower than their surroundings, so walls are held uniform and ribs are sized at 50 to 60 percent of the adjacent wall. Where a boss or thick boss root cannot be avoided, the surface is usually cored out or textured so any remaining mark is invisible.
6. What causes a visible weld line and can you move it?
A weld line appears where two melt fronts meet, and it will appear somewhere on almost every part. What we control is where. Gate position and fill balance are set during the review so the line falls on an edge or behind a rib rather than across a visible face, and the trial confirms it landed there before production starts.
7. Can you match an existing appliance panel colour?
Usually yes. Send a physical sample or the Pantone or RAL reference and we will match it in resin, then measure the result. Worth knowing that unpainted parts will drift slightly between lots over a long programme, so if you need a replacement panel to match perfectly five years later, painting is the honest answer.
8. What is the realistic life of a production tool for an appliance programme?
It depends on the resin and the finish. A hardened steel tool for unfilled ABS or PP will comfortably run several hundred thousand shots in normal service. Glass filled material is abrasive and cuts that figure, which changes the steel choice. We quote against your expected annual volume so the tooling grade matches what you actually need.
9. Do you handle assembly or only the moulded parts?
We handle both. Sub-assembly with heat staking, ultrasonic welding, threaded inserts and finished assembly are all available, and doing it here means one purchase order covers the mouldings and the built assembly. If you prefer to receive parts only, that works too, and we pack to your line requirements.
10. What quantity makes steel tooling worthwhile over aluminium?
Around 20,000 pieces a year is where steel generally becomes the better answer for a single part number. Below that aluminium tooling often carries the volume at lower total cost. We quote both with the amortisation shown so you can see the crossover on your own numbers rather than on a rule of thumb.
11. Can you help replace a metal bracket with a plastic part?
Yes, and it usually works when cost or corrosion is the driver rather than ultimate strength. The honest part of the analysis is stiffness, because plastics are far less stiff than steel, so the replacement is normally ribbed and often glass filled. Send us the existing part and load case and we will tell you whether it is viable.
12. How do you handle parts that must mate with existing components?
Send the mating part or a STEP file of it and we will design the fit interface against it, then verify with a fixture at first article. This is the most important thing you can give us. A panel that meets its own drawing perfectly can still fail to assemble if the interface was only ever verified numerically.
13. What is the lead time for a new appliance programme?
Aluminium pilot tooling is 2 to 3 weeks and gets you real parts quickly. Production steel tooling is 4 to 6 weeks from frozen design. We review the part in the first 24 hours, and often the review finds a change worth making, which is the real reason to send drawings early rather than late.
14. Can you run outdoor UV resistant parts?
Yes for the right grade. UV stabilised PP and ASA handle outdoor exposure where standard HIPS and ABS will chalk and fade. Tell us the intended service life and location, since a part that sits outside for five years in direct sun needs a different package from one that sits outdoors under cover.
15. What file types do you need to quote?
A 3D model in STEP or IGES, a 2D drawing with tolerances and cosmetic callouts, the target material if you have one, the annual volume and any safety requirement such as flame rating or food contact. If the material is undecided, describe the service conditions and we will propose two candidate grades with reasoning.
16. Do you offer third-party inspection?
Yes. We arrange SGS, Bureau Veritas or TUV at any stage you specify, from resin verification through to the pre-shipment check. For a first shipment from a new supplier inspection is usually worth doing once, since it establishes a neutral baseline that every subsequent lot can be measured against.