Electric pot moulding

Through our rich experience and perfect supply chain, our company can provide customers with high-quality customized Electric pot 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 Electric pot moulding moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

The plastic housing of an electric rice cooker represents a quintessential example of an injection-molded appliance component—one subjected to high temperatures and humidity, prolonged thermal exposure, and strict food-grade safety requirements, while simultaneously prioritizing both aesthetic appeal and structural integrity. Key components typically include the top lid, main housing body, base, steam vent cover, control panel, inner pot decorative ring, buttons, latches, and inner lid support brackets. Given its operational environment—characterized by elevated temperatures, high moisture levels, and prolonged cycles of thermal fluctuation—these plastic parts are subject to exceptionally rigorous demands regarding heat resistance, dimensional stability, aging resistance, resistance to stress cracking, and food-contact safety. The injection molding process therefore necessitates meticulous control centered on five core principles: resistance to heat-induced deformation, resistance to moisture-induced cracking, dimensional stability, a high-gloss surface finish, and safety (non-toxicity). The specific key considerations are outlined below.

Material selection is primarily guided by the principles of heat resistance, moisture resistance, food-grade compliance, and high rigidity. For large exterior components—such as the main housing and top lid—materials such as heat-resistant ABS, modified PP, or reinforced PP are commonly employed. These materials must possess a heat resistance rating of 110–130°C to withstand prolonged thermal radiation and steam exposure without softening, deforming, or yellowing. Heat-resistant ABS is favored for the exposed parts of high-end models due to its superior gloss, rigidity, and stable shrinkage characteristics; conversely, PP is frequently utilized for structural components—such as bases and rear covers—owing to its lower cost, excellent moisture resistance, and inherent toughness. Precision components—including control panels, buttons, and decorative rings—typically utilize PC/ABS alloy, which offers enhanced impact strength and dimensional stability, thereby minimizing the risk of whitening or cracking caused by temperature fluctuations. Components likely to come into contact with moisture or food—such as the inner pot rim and the areas surrounding the steam vents—must be fabricated using food-grade PP or food-grade ABS. These materials must strictly adhere to food-contact safety standards, ensuring they remain odorless, free of toxic leachates, and resistant to aging caused by exposure to boiling water. Furthermore, all components exposed to water or heat must possess robust resistance to hydrolysis and stress cracking to prevent embrittlement, deformation, or discoloration during prolonged operation within a hot and humid environment. Regarding raw material pretreatment: ABS and PC/ABS exhibit strong hygroscopicity and require hot-air drying at 80–90°C for 3–4 hours to reduce moisture content to below 0.03%; this prevents the formation of silver streaks, bubbles, or a matte finish during molding. PP, having low hygroscopicity, does not require extensive drying; however, in humid environments, it should be preheated at 70°C for one hour to eliminate surface moisture marks.

Mold design focuses on resolving issues related to the warping of large flat surfaces, dimensional stability in humid and hot environments, precision assembly, and demolding. Rice cooker housings typically feature deep cavities, large curved surfaces, numerous reinforcing ribs, and multiple snap-fit locations. The parting line is positioned along the maximum contour—avoiding visible exterior areas—and the mold-closing clearance is controlled to within 0.02 mm to minimize flash and burrs that could compromise assembly integrity and sealing performance. The mold cavity and core are constructed from 718 or S136 mold steel and polished to a surface roughness of Ra 0.02–0.05 μm to ensure the housing possesses a uniform gloss, is free of weld lines, and is easy to clean. For large-area housings, reinforcing ribs must be strategically arranged, with rib thickness controlled at 50–60% of the main wall thickness to prevent sink marks and warping caused by heat exposure. Assembly holes, locating posts, and snap-fit features are machined with high precision—maintaining dimensional tolerances within ±0.05–0.1 mm—to ensure a tight, secure fit with the inner pot, heating plate, and lid assembly, thereby preventing steam leakage. The mold dimensions must be precisely compensated based on the material's shrinkage rate—0.5–0.7% for ABS and 1.2–1.8% for PP—to prevent assembly gaps from widening or snap-fits from loosening after prolonged use at high temperatures.

For the gating system, priority is given to hot runners or multi-point side gates; for large housings, a balanced dual-point injection system is employed to shorten the filling flow path and minimize weld lines and internal stresses. Gate locations are positioned discreetly so as not to compromise the exterior aesthetics or the integrity of mating surfaces. The cooling system is critical for controlling deformation; cooling channels are distributed uniformly along the contours of the housing. In deep cavity and thick-walled regions, the density of these channels is increased to ensure that mold temperature fluctuations remain within ±3°C, thereby guaranteeing uniform cooling and minimizing warpage and internal stress. Particular emphasis is placed on vent design; vent grooves with a depth of 0.02–0.03 mm are strategically placed at the ends of deep cavities, the bases of ribs, and corners to prevent trapped gas burns, short shots, and voids. Structural features on the pot lid and housing—such as undercuts, grooves, and snap-fit clips—are demolded using sliders or angled ejectors to ensure smooth ejection without drag marks or stress whitening, thereby preventing the propagation of micro-cracks in humid and hot environments.

The core objectives of the injection molding process are dimensional stability, deformation prevention, low internal stress, and high surface finish. Equipment selection focuses on injection molding machines with a clamping force of 160–500 tons, utilizing an injection volume equivalent to 1.2–1.5 times the product weight to ensure thorough plasticization and stable injection. Temperature settings are segmented: for heat-resistant ABS, the barrel temperature is set to 220–260°C and the mold temperature to 50–70°C to enhance surface quality and reduce internal stress; for PP, the barrel is at 190–220°C and the mold at 40–60°C to balance crystallization shrinkage and minimize thermal deformation; and for PC/ABS, the barrel is at 240–270°C and the mold at 60–80°C to improve dimensional stability. Injection speed employs a three-stage control profile: an initial low-speed phase prevents jetting; a mid-speed phase fills the main body of the part; and a final low-speed phase maintains pressure stability, preventing trapped gas and flash.

Injection pressure is set between 80–130 MPa, adjusted according to wall thickness and structural complexity, with slightly higher pressures applied for deep cavities and thin-walled parts. Holding pressure is set to 60%–75% of the injection pressure, with a holding time of 10–25 seconds; this phase focuses on compensating for shrinkage at assembly points and corners, thereby eliminating sink marks and depressions. Back pressure is maintained at 3–6 MPa to enhance melt homogeneity and prevent color variations or uneven color mixing. The cooling time is controlled within a range of 20–40 seconds, depending on the wall thickness, to ensure the product is fully set before ejection, thereby preventing deformation or sticking to the mold. Ejection is executed using a combined ejector plate and pin system, ensuring uniform force distribution and preventing "ejector marks"—such as whitening or protrusions—from appearing on large flat surfaces.

Post-processing and quality inspection are conducted in strict compliance with safety standards for home appliances and cookware. Following molding, gates, flash, and burrs are meticulously removed. Aesthetic components are inspected for color variation, scratches, weld lines, and surface gloss; structural components are checked for installation hole spacing, flatness, and snap-fit strength. Dimensional tolerances are controlled within ±0.05–0.1 mm to ensure stable assembly. Reliability testing includes: high-temperature resistance tests (withstanding exposure to 110–125°C environments for 2–4 hours without softening, deformation, or yellowing); and humid-heat aging tests (withstanding prolonged exposure to high-temperature, high-humidity environments without cracking, discoloration, or stress-induced whitening). Components intended for food contact undergo specific odor and safety testing to ensure they are free of off-odors and do not leach toxic substances.

Regarding the prevention and control of common defects: Warping and deformation of the housing are often caused by uneven cooling, improper mold temperatures, or excessive internal stress; these issues require optimizing cooling channel layouts, extending cooling times, and adjusting holding pressure. Sink marks and depressions typically result from overly thick ribs or insufficient holding pressure; solutions involve optimizing the structural design and increasing the holding pressure. Silver streaks and matte surface finishes are caused by moisture in the raw material; strict drying protocols must be enforced. Prominent weld lines can be minimized by increasing the mold temperature and injection speed, as well as by enhancing venting. Flash (excess material) is usually caused by insufficient clamping force or mold wear; this requires increasing the clamping force and repairing the mold's parting line. Cracking in humid-heat environments is often attributed to excessive internal stress; this can be mitigated through annealing treatments or by reducing the injection pressure.

Overall, the core requirements for the injection molding of plastic rice cooker housings are heat and moisture resistance, dimensional stability, resistance to deformation and cracking, food-grade safety, and a uniform, aesthetically pleasing appearance. Through the meticulous control of the entire process—encompassing material selection, mold design, processing parameters, and quality inspection—the housing can maintain its stability and reliability even under prolonged exposure to high temperatures, high humidity, and alternating hot-and-cold cycles, thereby fulfilling the comprehensive requirements for rice cookers regarding safety, durability, sealing integrity, and aesthetics.

We are a Electric pot moulding moulding manufacturer, providing high-quality Electric pot moulding moulding manufacturing. As long as you want to customize/develop Electric pot 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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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.