High quality plastic parts food grade abs pp 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 high quality plastic parts food grade abs pp 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 high quality plastic parts food grade abs pp moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

Food-grade ABS and PP plastic parts are commonly used for food storage containers, water bottle housings, kitchenware handles, food machinery casings, children's tableware, food storage bins, and plastic components for beverage dispensers. These parts come into direct or indirect contact with oils, warm water, and hot or cold foods. Key performance requirements include food-contact safety, absence of odor, low VOC emissions, no leaching, resistance to high and low temperatures, freedom from internal stress-induced cracking, a clean surface free of black specks or silver streaks, and dimensional stability. As molding processes, raw material controls, mold specifications, and post-processing standards differ for these materials, the following section outlines the critical control points for high-quality molding across the entire process.

I. Raw Material Selection and Pre-treatment (The First Critical Step for Food-Grade Quality)

1. Material Classification and Compliance Requirements

1) Food-grade PP: Homopolymer or copolymer PP specifically designed for food applications; resistant to 100°C boiling water and oils; free from plasticizer leaching; suitable for tableware, food storage boxes, and food containers.

2) Food-grade ABS: Medical or food-contact grade ABS; characterized by low residual monomers and low styrene emission; commonly used for kitchenware handles, equipment housings, and transparent food-related components; not suitable for prolonged boiling or steaming; temperature resistance range: -20°C to 70°C.

Strict Prohibition on Regrind Usage

The addition of any regrind (reprocessed sprue/runner material) is strictly prohibited for cavities, inner liners, or tableware components that come into direct contact with food, as impurities and degraded small molecules in regrind can leach and contaminate the food. Only external, non-contact decorative parts may incorporate up to 5% of clean, virgin-grade regrind of the same material type; this material must be granulated and dust-filtered separately.

Specifications for Mixing and Additives

Use only food-grade, odorless masterbatches and food-certified, low-leaching mold release agents. The use of standard industrial fillers or plasticizers is strictly prohibited, as is the addition of materials containing heavy metals or flame retardants. PP and ABS must be mixed and stored in separate hoppers to prevent cross-contamination.

Mixing should be performed in a low-speed, sealed mixer for 5–10 minutes at a speed of 260–300 rpm to minimize frictional heat generation and the resulting odors. 2. Drying and Dehumidification Standards (Eliminating silver streaks, odors, and migration risks)

1) Food-grade ABS: Highly hygroscopic; moisture causes internal micropores, odors, and excessive migration. Dry with constant-temperature hot air at 80°C for 3.5–4 hours; moisture content must be ≤0.03%.

2) Food-grade PP: Negligible water absorption; generally requires no drying. In high-temperature/high-humidity workshops, low-temperature drying at 60°C for 60 minutes is sufficient to remove surface condensation.

Dried material must be conveyed via sealed barrels and hoppers to isolate it from workshop oil, dust, and moisture; open-air storage is prohibited.

3. Barrel Purging Protocols

Before changing materials, colors, or switching between food-grade and industrial-grade materials, the barrel must be thoroughly purged using dedicated food-grade purging compound. The purging temperature should be 10–15°C higher than the molding temperature. Purging continues until the output is pure and free of discoloration, preventing excessive migration of trace contaminants from different materials.

II. Design and Machine Setup Controls for Food-Grade Molds

1. Mold Steel and Hygiene Standards

Cavities must be made of corrosion-resistant, mirror-finish stainless steel (S136/STAVAX) with a fully polished surface (Ra ≤ 0.02μm) to facilitate cleaning and prevent the accumulation of oil or residual plastic oligomers. The use of standard P20 or 718 steels without anti-corrosion treatment is prohibited, as long-term production can lead to corrosion and the migration of metallic impurities.

All internal corners must feature radius (R) fillets to eliminate dead zones where material or grime could accumulate. Parting surfaces require high-precision grinding, with flash controlled to within 0.01mm to prevent fine debris from contaminating the food.

2. Balanced Cooling System (Controlling deformation and migration)

Food containers are typically thin-walled square or round shells (wall thickness 1.6–2.2mm). Thick-walled support pillars feature internal spiral cooling cores, and cooling channels are arranged symmetrically to minimize temperature differentials and internal stress.

Mold temperature zones: 50–60°C for food-grade ABS; 30–40°C for food-grade PP. Excessive mold temperatures accelerate additive migration and odor generation; conversely, excessively low temperatures induce high stress, leading to cracking caused by thermal cycling.

3. Contamination-prevention design for venting and ejection

Each cavity features multiple independent, precision-engineered venting channels (0.010–0.012 mm deep) to effectively exhaust low-molecular-weight volatiles released during heating, thereby minimizing odor and migration risks.

Ejector pins and sleeves are fully polished, and a multi-point, symmetrical, low-speed ejection process is employed to prevent stress marks ("whitening") and micro-cracks (which can harbor oil and bacteria).

The mold cooling system utilizes purified water circulation to eliminate the risk of cavity contamination from rust or impurities found in standard industrial circulating water.

4. Cleanliness requirements for machine setup

Before installation, mold parting surfaces and cavities are thoroughly wiped down and degreased with alcohol. Dust-proof sealing covers are installed on machine hoppers and feed inlets. Production of food-grade components takes place in designated workshop zones, isolated from areas involving machine oil, cutting fluids, or dust. Low-pressure mold-clamping protection is calibrated to prevent cavity impact damage or rust.

III. Injection Molding Process (Focus on Low Migration and Low Stress)

1. Zoned low-temperature barrel control (Strict control of migration and odor)

1) Food-grade ABS: Feed zone 160°C, intermediate zones 175–190°C, nozzle 195°C (max. 200°C). Excessive temperatures cause significant styrene monomer volatilization, leading to unacceptable odor and migration levels.

2) Food-grade PP: 185–210°C, nozzle 210°C (strictly below 220°C). High temperatures degrade the food-grade anti-migration additives.

The process adheres to the principle of low-temperature molding: melt temperatures are kept as low as possible—while still ensuring complete mold filling—to minimize the volatilization of low-molecular-weight compounds.

2. Zoned, low-speed, gentle filling

A three-stage variable speed profile is used: low-speed buffering at the gate, uniform-speed filling in the middle section, and significantly reduced speed at the end of the cavity to facilitate venting. This approach minimizes molecular chain scission and the generation of low-molecular-weight fragments caused by high shear forces. Injection pressure: 70–100 bar; lower pressure minimizes internal stress and the risk of material precipitation.

3. Low-pressure, staged, short-duration holding

PP exhibits significant crystallization shrinkage, so a two-stage low-pressure holding phase is set for compensation; ABS has low shrinkage, so the holding time is shortened. Holding time is 4–9s for thin-walled food containers and 10–15s for thick-walled bases. High-pressure, long-duration holding is prohibited to prevent internal stress accumulation.

4. Sufficient low-temperature cooling

Cooling time is calculated at 3–4s per 1mm of wall thickness (e.g., 8–12s for a 2mm food box); insufficient cooling leads to shrinkage, deformation, and invisible micro-cracks after demolding.

Mold opening and ejection must be performed smoothly at low speeds; parts are removed via robotic arm. Manual contact with food-contact surfaces is prohibited to avoid contamination from skin oils.

IV. Post-processing: Shaping, stress relief, and cleaning

Dust-free gate burr trimming

Use only food-grade non-metallic grinding tools or small pneumatic soft grinding heads to eliminate metal dust generation; for vibratory finishing, use food-specific grinding media, followed by rinsing with purified water and air drying.

Annealing for stress relief (Mandatory for ABS; optional for PP)

Food-grade ABS parts must undergo constant-temperature annealing in a dust-free oven at 60°C for 1.5–2 hours, followed by slow cooling to release internal stress and prevent cracking or coating delamination during thermal cycling;

PP containers have low internal stress but may undergo short-duration, low-temperature annealing if intended for long-term use involving thermal cycling.

Cleaning and dust removal

After molding, parts are purged with a dust-free air gun; spraying food-contact surfaces is prohibited. If printing is required, use only food-grade eco-friendly ink, followed by a second dust-removal step.

Parts with slight warpage are corrected at low temperatures using stainless steel shaping jigs to ensure a tight, secure seal.

Isolated storage

Semi-finished products are placed on dedicated dust-free trays, kept away from the floor, oil contamination, and standard plastic turnover crates. V. Multi-stage Quality and Safety Testing (Specific to Food-Contact Parts)

First-article dimensional and full visual inspection: No silver streaks, air bubbles, black spots, stress marks (whitening), cracks, or flash;

Odor test: No pungent plastic odor after immersion in warm water;

Leaching/migration spot checks: Testing for substances leached during immersion in warm water and oil/fat; compliance with national standards for food-contact plastics;

High/low-temperature cycling test: No cracking or whitening when alternating between boiling water and freezing temperatures;

Drop test: No breakage or shedding of fragments after a 1.2-meter drop.

All non-conforming food-contact parts are scrapped; grinding and reusing them for food-contact components is strictly prohibited.

VI. Packaging and Warehousing

Qualified products are individually sealed in food-grade PE dust-free bags and stored in a dry, light-protected area, segregated from industrial plastic parts; raw material test reports and molding process records are retained for each batch to ensure full-process traceability regarding food safety.

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