Small plastic moulding parts 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 small plastic moulding parts 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 small plastic moulding parts moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

Small injection-molded parts generally refer to lightweight, compact plastic components with wall thicknesses of 1–2.5 mm, typically produced using multi-cavity molds (8, 16, 32, or more cavities). Examples include electronic connector terminals, snap-fits, gaskets, gears, switch bases, wire harness sleeves, small appliance brackets, metal-plastic bushings, toy components, and equipment sealing plugs. These parts are characterized by short melt flow paths, rapid filling speeds, restricted venting space, delicate ejector pins prone to punching through the part, and stringent requirements for dimensional consistency across batches. Certain precision components must also meet specific criteria regarding assembly tolerances, wear resistance, flame retardancy, waterproofing, and temperature resistance. Molding control focuses on five core areas: raw material drying, multi-cavity mold balancing, high-speed filling and venting, precision temperature control to minimize deformation, and protection during micro-ejection. The key molding points for each module are detailed below.

I. Raw Material Pre-treatment and Molding Essentials

Although small parts require minimal material per shot and involve short screw residence times, high-shear conditions can easily lead to material degradation, fiber exposure, and silver streaking; therefore, raw material pre-treatment standards must not be compromised.

Raw Material Selection and Regrind Management

ABS or modified PP is selected for general-purpose cosmetic parts; POM or PA6 reinforced with glass fiber is used for precision wear-resistant gears and sliding snap-fits; flame-retardant PA or PC/ABS is used for electronic connectors and switch bases; and PC is used for small transparent lenses and indicator covers.

The use of regrind (sprue/runner scrap) is strictly prohibited for small precision load-bearing parts and flame-retardant electronic components, as impurities and degraded molecules in the regrind can compromise structural strength and flame-retardant properties. For standard decorative parts, the regrind addition ratio must be kept below 10%; the material must be uniformly granulated and sieved to remove coarse particles, preventing uneven filling across multiple cavities. Low-blooming mold release agents are used in material blends to prevent surface blooming or assembly jamming at the parts' tight-tolerance mating surfaces. Glass-fiber-reinforced materials are mixed at low speeds to minimize fiber breakage and ensure consistent wear resistance in the finished parts. **Material Mixing Operational Guidelines**

Use a small vertical mixer at a speed of 250–300 rpm; a mixing time of 5–8 minutes is sufficient—prolonged mixing is unnecessary. Mix small parts of different colors separately and precisely control the masterbatch ratio to prevent batch-to-batch color variations. Store flame-retardant materials and nylon separately; do not mix them with PP or ABS to avoid compromising material properties. Seal the mixing drum after processing to exclude dust; fine dust entering a multi-cavity mold can easily cause blocked venting and black spots on the product.

**Mandatory Drying and Dehumidification Requirements**

PC, PA, and PC/ABS are highly hygroscopic; even tiny bubbles can cause dielectric breakdown in electronic components or structural failure in load-bearing parts. Dry PC at 110°C for 4 hours, PA6+GF at 110°C for 4 hours, and ABS at 80°C for 3 hours. PP and POM have low water absorption; simply dry them at 60°C for 1 hour in humid environments to remove surface moisture. Given the small hopper capacity of small machines, dry raw materials in small batches to avoid re-absorption of moisture during prolonged storage; re-dry materials if the machine is idle for more than one hour.

**II. Design and Machine Setup for Small Multi-Cavity Molds**

Molds for small parts typically feature multi-cavity layouts. Key challenges include balancing melt flow across cavities, venting narrow areas, and preventing fine ejector pins from punching through the part.

**Mold Steel and Structure**

For small parts with cosmetic requirements, use 718H or S136 mirror-finish steel to ensure a scratch-free surface after polishing. Apply nitriding treatment to molds for glass-fiber-reinforced or POM parts to withstand high-speed melt erosion. Design all corners with a radius of at least R0.5; sharp corners in tiny parts create stress concentrations that make them prone to snapping. Maintain parting line fit accuracy within ≤0.01mm to eliminate fine flash that could interfere with assembly.

**Runner Balancing Design (Core of Multi-Cavity Molds)**

For 16-cavity or 32-cavity molds, use a balanced runner system where runner lengths and diameters are identical for all cavities; this prevents issues such as short shots (under-filling) or flash (over-filling) in specific cavities. For small parts, point gates or side gates are preferred; their small dimensions minimize the need for post-molding trimming. Precision gears utilize submarine gates that automatically shear off, thereby enhancing automation efficiency.

Cooling and Venting Optimization

Small parts feature thin walls and cool rapidly, yet fine ribs and bosses are prone to heat accumulation and sink marks. The mold employs a dense network of fine cooling channels positioned close to the cavities to ensure uniform mold temperatures. A mold temperature controller provides precise regulation: 50–60°C for ABS, 80–90°C for POM, and above 80°C for glass-fiber reinforced nylon.

Small parts are highly susceptible to gas entrapment defects. Independent venting slots (0.010–0.012 mm deep, 3–5 mm wide) are cut for each cavity, and venting inserts are added at ribs, weld lines, and flow-end positions to facilitate rapid gas evacuation during high-speed filling, preventing burning, short shots, and brittle weld lines.

Ejection System Protection

Ejector pins for small parts have small diameters (φ1–φ3 mm); high-speed ejection risks punching through the part or causing stress whitening. A combination of multiple fine pins, sleeve ejectors, and flat ejectors is used, with pins positioned at thick-walled areas away from cosmetic or mating surfaces. A two-stage ejection speed profile—slow initial release followed by rapid ejection—is employed to minimize localized stress. For slender, sleeve-like parts, ejector blocks are added to prevent bending or deformation during demolding.

Mold Commissioning

Small parts are produced on 100T–300T injection molding machines; multi-cavity molds require sufficient clamping force to prevent mold opening or flashing during high-speed injection. Cooling channels are individually flushed to ensure no blockages, and low-pressure mold protection is calibrated to trigger automatic mold opening even with minute gate residue, preventing damage to delicate cavities. Before producing flame-retardant parts, the injection barrel is thoroughly cleaned to remove residues from other materials.

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