Washing machine moulding

In addition, our company has established cooperative relationships with plastic raw material suppliers, printing manufacturers, etc. to ensure the supply of raw materials and printing quality. Through our rich experience and perfect supply chain, our company can provide customers with high-quality customized washing machine moulding moulding products to meet their specific needs. At the same time, we have 10 years of professional foreign trade service experience, understand the foreign trade process, and better serve our customers. For washing machine moulding moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

As a core aesthetic and structural component of home appliances, the washing machine housing requires injection molding processes that balance dimensional precision, surface quality, structural integrity, and production efficiency. From material selection and mold design to process parameter control and post-processing quality inspection, every step demands meticulous control. The following outlines the complete molding details and key considerations.

I. Material Selection and Pre-treatment (The Foundation of Molding)

1. Mainstream Materials and Their Characteristics

Washing machine housings typically utilize three main material types—ABS, PP, and PC/ABS alloys—each tailored to suit different product positioning and performance requirements:

ABS (Acrylonitrile-Butadiene-Styrene): The preferred choice for mid-to-high-end models. It offers excellent rigidity, high impact resistance, superior surface gloss, and is easy to paint or screen-print. With a shrinkage rate of 0.5%–0.8% and a molding temperature range of 220°C–260°C, it is ideal for components featuring complex aesthetics and intricate structural designs.

PP (Polypropylene): The mainstream choice for economy-class models. It features low cost, chemical resistance, low-temperature durability, and low density. With a shrinkage rate of 1.0%–2.5% (higher due to its crystalline nature) and a molding temperature range of 180°C–220°C, it often requires the addition of anti-aging agents and tougheners to enhance performance. It is well-suited for structural components such as the top covers and bases of drum-type washing machines.

PC/ABS Alloy: Reserved for high-end models. This alloy combines the high rigidity and heat resistance of PC with the ease of processing characteristic of ABS. It offers exceptional impact resistance and dimensional stability, making it suitable for ultra-thin, high-strength housing applications. The molding temperature range is 240°C–280°C.

2. Raw Material Pre-treatment (A Critical Preliminary Step)

The hygroscopic nature of plastic raw materials can lead to molding defects such as bubbles, silver streaks, and surface blemishes; therefore, proper pre-treatment is a critical prerequisite:

Drying Treatment: ABS and PC/ABS materials require hot-air drying at a temperature of 80°C–90°C for 3–4 hours, with the moisture content strictly controlled to remain below 0.03%. PP, being less hygroscopic, allows for a simplified drying process (70°C–80°C for 1–2 hours). Mixing and Color Matching: The housing requires a uniform color tone; color masterbatch is added in a specific ratio (2%–5%) and thoroughly blended using a mixer to prevent color variations. For functional housings, flame retardants and anti-static agents are added to enhance safety and operational performance.

II. Mold Design and Manufacturing (The Core of Molding Precision)

The washing machine housing is a large, thin-walled component (wall thickness: 1.5–3 mm); thus, the mold design directly determines the quality and efficiency of the molding process:

1. Mold Structure Design

Parting Line Selection: Positioned along the maximum contour of the housing while avoiding visible exterior surfaces. Any misalignment of the parting line is controlled within 0.02 mm to prevent flash and visible mold-closing marks.

Cavity and Core: An integral cavity design is employed to ensure surface flatness. The core features reinforcing ribs (with a thickness equal to 50%–60% of the housing's wall thickness) to enhance structural strength and prevent deformation. For large housings, multi-cavity molds (2–4 cavities) are utilized to boost mass production efficiency.

Gating and Runner System: The main runner diameter is 6–8 mm, and the sub-runner diameter is 4–6 mm. A hot runner system is adopted to minimize gate waste and shorten the molding cycle. Side gates or submarine gates are selected; their placement avoids visible exterior surfaces, with a gate diameter of 0.8–1.2 mm and a length of ≤1.5 mm to ensure uniform melt filling.

Cooling System: Mold cooling channels have a diameter of 8–10 mm and are distributed uniformly along the cavity and core. The temperature of the stationary mold is maintained 3–5°C higher than that of the moving mold, with cooling water temperatures ranging from 20°C to 30°C, to ensure uniform cooling of the housing and minimize internal stress and sink marks.

Venting System: Venting slots are positioned at the final filling points of the melt (e.g., corners, ends of reinforcing ribs). These slots have a depth of 0.025–0.038 mm and a width of 1.5 mm, serving to expel air from the mold cavity and prevent trapped-air burns or voids. 2. Mold Materials and Processing

The mold cavities and cores are constructed using 718 pre-hardened steel (offering superior overall performance and suitability for high-precision molds) or S136 stainless steel (corrosion-resistant and ideal for high-gloss housings). The surfaces are polished to a roughness of Ra 0.02–0.05 μm to ensure a flawless finish on the final housing.

Processing is executed using CNC milling, EDM (Electrical Discharge Machining), and wire cutting. The cavity dimensions are compensated based on the material's shrinkage rate (ABS: +0.6%; PP: +1.5%) to ensure that the dimensions of the molded parts meet specifications.

3. Control of Injection Molding Process Parameters (Critical Molding Stages)

A large-scale horizontal injection molding machine is selected for this process (featuring a clamping force of 1,000–3,000 tons and an injection volume of ≥1,000 g). Control focuses on four core parameters—temperature, pressure, speed, and time—which are subject to precise, stage-by-stage management:

1. Temperature Parameters (Core of Melt State Control)

Barrel Temperature: A gradient heating profile is applied (from the feed zone → middle zone → front zone → nozzle). For ABS: Feed zone 220°C, middle zone 240°C, front zone 250°C, nozzle 245°C. For PP: Feed zone 180°C, middle zone 200°C, front zone 210°C, nozzle 205°C. Temperature fluctuation is maintained within ≤ ±5°C to prevent material degradation or insufficient mold filling.

Mold Temperature: For ABS, the mold temperature is set to 60–80°C (to enhance surface gloss and reduce internal stress). For PP, the mold temperature is set to 50–70°C (to control crystallinity and minimize shrinkage). Mold temperature stability is maintained within ≤ ±3°C to ensure uniform cooling. 2. Pressure and Speed Parameters (Core of Filling and Holding Phases)

Injection Pressure: ABS 100–140 MPa; PP 120–160 MPa. Controlled in three stages: Low speed (5%–10%) for filling the gate (to prevent flash) → Medium-to-high speed (60%–80%) for filling the main body of the cavity (to reduce cycle time) → Low speed (10%–20%) for filling the final section (to prevent voids/bubbles).

Holding Pressure: 60%–80% of the injection pressure (ABS 70–110 MPa; PP 90–130 MPa). Holding time is 15–25 seconds—until the gate freezes—to compensate for melt shrinkage and eliminate sink marks and depressions.

Back Pressure: 3–8 MPa, ensuring uniform and dense plasticization of the melt while preventing voids.

Clamping Force: Calculated based on the projected area (3000–3800 t/m²), using the threshold of "just barely no flash" as the standard to prevent mold deformation.

3. Time Parameters (Core of Molding Efficiency)

Injection Time: 3–5 seconds for large housings, ensuring rapid filling of the melt and minimizing uneven cooling.

Cooling Time: Accounts for 60%–80% of the total molding cycle. ABS: 40–60 seconds; PP: 30–50 seconds. The standard is defined as the point where the housing can be ejected without deformation or sticking to the mold.

Total Molding Cycle: ABS: 70–90 seconds; PP: 60–80 seconds. The cycle is shortened—and production capacity increased—through the optimization of cooling processes and the use of hot runner systems.

We are a washing machine moulding moulding manufacturer, providing high-quality washing machine moulding moulding manufacturing. As long as you want to customize/develop washing machine moulding moulding products, you can find us. We have professional injection mold design and mature manufacturing technology, providing you with one-stop service, from product design-mold making-product production-product packaging-product transportation, we can help you in every link. As long as you come to us, we will provide you with the ultimate service and satisfy you in terms of product quality, production time, information dialogue, etc.

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Factory

We are Custom Plastic Mold factory. Our factory is plastic injection mold maker. we has 17 years of experience in professional custom plastic mold and 10 years of foreign trade experience. We are custom Plastic Mold supplier. We can provide custom Plastic Mold service. Our factory can make the Injection molded plastic parts, and the quality of the products will satisfy you.

We have more than 50 high-end machines and hundreds of engineers and designers. We can provide one-stop service, from product design - mold making - product production - product packaging - transportation. We have a complete production chain. We can meet all your requirements.

Services we provide:

Professional custom mold service, Plastic mold design and manufacturing .plastic product production, product design, mold design, blow mold customization, rotational mold customization, die-casting mold customization. 3D printing services, CNC manufacturing services, product packaging, customized packaging, shipping services.

We always adhere to the principles of quality first and time first. While providing customers with the highest quality products, try to maximize the production efficiency and shorten production time. We are proud to tell every customer that our company has not lost any customer since its establishment.If there is a problem with the product, we will seek a solution actively and take responsibility to the end.

FAQ

Q1: Are you trading company or manufacturer ?

A: We are manufacturers.

Q2. When can I get the quotation?

A: We usually quote within 2 days after we get your inquiry.

If you are very urgent, please call us or tell us in your email so that we can quote for you first.

Q3. How long is the lead-time for mold?

A: It all depends on the products' size and complexity. Normally, the lead time is 25 days.

Q4. I have no 3D drawing, how should I start the new project?

A: You can supply us a molding sample, we will help you finish the 3D drawing design.

Q5. Before shipment, how to make sure the products quality?

A: If you don't come to our factory and also don't have the third party for inspection, we will be as your inspection worker.

We will supply you a video for production process detail include process report, products size structure and surface detail, packing detail and so on.

Q6. What is your payment terms?

A: Mold Payment: 40% deposit by T/T in advance, 30% second mold payment before sending out the first trial samples, 30% mold balance after you agree the final samples.

B:Production Payment: 50% deposit in advance, 50% before sending out the final goods.

Q7: How do you make our business long-term and good relationship?

A:1. We keep good quality and competitive price to ensure our customers benefit for best quality products.

2. We respect every customer as our friend and we sincerely do business and make friends with them, no matter where they come from.