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

Motorcycle plastic components—including the body shell, front fairing, side panels, tail cowl, fenders, instrument housing, footwell guards, battery box, helmet liner brackets, and handlebar covers—fall into two main categories: aesthetic bodywork and load-bearing structural parts. These components must withstand high-speed wind resistance, outdoor exposure (sun and rain), vehicle vibration, stone impacts, and extreme temperature fluctuations over the long term. Certain load-bearing parts must also meet specific requirements for impact resistance, oil corrosion resistance, and UV aging resistance; consequently, the overall injection molding control standards are significantly higher than those for electric scooter plastics. The complete molding process comprises five key stages: raw material pretreatment, mold assembly and debugging, the injection molding cycle, post-processing/shaping, and multi-stage reliability inspection.

I. Raw Material Warehousing and Pretreatment

Mainstream materials for exposed motorcycle bodywork include ASA and weather-resistant ABS+PC alloys; battery boxes and load-bearing footwell structures utilize modified PP or PA6 reinforced with 30% glass fiber; and transparent instrument covers use high-impact PC. All incoming raw materials must be accompanied by test reports verifying RoHS compliance, weather resistance, and chemical corrosion resistance. Aesthetic parts are manufactured exclusively from virgin resin, with a maximum regrind (sprue/runner) content of 10%; the use of reground material is strictly prohibited for load-bearing components—such as frame connectors and structural brackets—to prevent any reduction in impact strength.

For coloring, weather-resistant masterbatches are used in conjunction with UV-resistant additives and low-migration, oil-resistant mold release agents. The mixture is blended in a vertical mixer at low speed for 8–12 minutes, with rotational speed carefully controlled to prevent frictional heat from causing pigment agglomeration or polymer degradation. Glass-fiber-reinforced nylon is mixed separately to minimize fiber breakage, which would otherwise compromise product rigidity.

Drying and dehumidification are critical processes for controlling surface defects: ASA and ABS+PC bodywork components undergo hot-air drying at 85°C for 4 hours, while transparent PC parts are dried at 110°C for 6 hours using a dehumidifying dryer, ensuring moisture content remains below 0.02%. Insufficient drying can lead to defects such as silver streaks and air bubbles, as well as large-scale paint delamination (popping) after the painting process. PA6+GF30 nylon is highly hygroscopic and requires dehumidifying drying at 110°C for 4–5 hours; after drying, the raw material must be conveyed in a sealed system to prevent re-absorption of moisture. Modified PP has extremely low water absorption; drying at 60°C for one hour in a humid environment to remove surface moisture is sufficient. Large-scale factories utilize central material feeding systems to completely isolate raw materials from dust and oil contamination.

II. Mounting and Preheating/Commissioning of Large Body Panel Molds

Motorcycle fairings and tail cowls are large-area, thin-walled plastic parts typically produced using large single-cavity molds, with targeted reinforcement of mold steel, cooling, venting, and ejection systems. Cavities for visible surfaces utilize S136 mirror-finish stainless steel, polished to be free of pits or scratches to meet painting and coating requirements; structural molds for glass-fiber reinforced nylon feature nitrided cavities to withstand long-term erosion and wear from hard glass fibers, thereby extending mold service life.

To address uneven wall thickness distribution, spiral cooling cores are installed within thick-walled ribs and mounting bosses, while the main shell body employs conformal cooling channels to balance cooling rates and mitigate shrinkage and warpage in large-area housings. Continuous, fine venting slots (0.015 mm deep) are machined at parting lines, corners, and weld line locations to rapidly evacuate trapped air during high-speed filling, preventing scorching or blackening at the edges. Long, slender components like fenders and side panels are equipped with multiple sets of balanced ejector pins and blocks to prevent bending, stress whitening, or cracking caused by uneven ejection forces.

The mold is hoisted onto a large-tonnage (650T–1200T) injection molding machine using an overhead crane, and clamping plates are tightened evenly to prevent platen deformation and flash during high-pressure injection. Cooling water and mold temperature control lines are connected, followed by a pressure test to check for leaks and a 30-minute mold preheating phase. Mold temperatures are maintained at 55–65°C for ASA cosmetic parts, 80–90°C for PC parts, and above 80°C for glass-fiber reinforced nylon parts. Low-pressure mold protection is preset; the mold opens automatically if residual runners or foreign objects are detected on the parting surface, preventing damage to the cavity caused by the clamping force of large molds.

III. Standard Injection Molding Cycle Process

The complete molding cycle comprises six steps: mold clamping, staged injection, two-stage holding pressure, constant-temperature cooling, mold opening and ejection, and automatic part removal by a robotic arm. The core of the process focuses on low-shear filling to minimize internal stress and enhance outdoor crack resistance.

Mold clamping involves four-stage speed control: slow closing, rapid advance, low-pressure protection, and high-pressure locking. Large-area body panels generate significant mold-opening forces during injection; high-pressure clamping ensures a tight fit at the parting surface, preventing continuous flash.

Precise zoned temperature control is applied to the barrel: 170–200°C for ASA housings, 190–260°C for ABS+PC, and 230–260°C for PA6+GF30 nylon. Strict adherence to temperature limits is required; excessive heat causes material decomposition (yellowing), reduced toughness, and compromised oil resistance. Injection utilizes multi-stage variable-speed filling: medium-to-high speeds are used for thin-walled housing areas to prevent premature melt cooling, which could lead to material shortages or short shots; low-speed injection is used for mounting posts and thick-walled bases to reduce molecular shear stress, thereby minimizing cracking issues during subsequent painting or thermal cycling. Injection pressure ranges from 90 to 130 bar; excessive pressure causes severe flash and a surge in internal stress, while insufficient pressure results in prominent weld lines and significantly reduced impact resistance.

Once the cavity is filled, the process switches to two-stage holding pressure to compensate for plastic shrinkage during cooling. Holding times are 15–22 seconds for thick-walled battery cases and 6–10 seconds for thin-walled panels, eliminating surface sink marks. During the holding phase, the screw simultaneously prepares material for the next cycle, thereby shortening the overall molding time.

Cooling time follows the guideline of 3–5 seconds per 1 mm of wall thickness; standard 2 mm panels require approximately 10 seconds of cooling. Continuous circulation of cooling water removes heat and stabilizes the mold temperature, preventing distortion or assembly misalignment caused by uneven cooling on one side of the housing. After cooling, the mold opens using a three-stage deceleration process, and the ejection mechanism gently releases the plastic part. A servo-driven robotic arm grips the housing to automatically trim gate waste, and the finished product is transferred to the assembly line; manual contact with visible surfaces is strictly prohibited throughout the process to prevent fingerprints or oils from compromising paint adhesion.

IV. Post-molding Processing, Annealing, and Surface Finishing

Freshly demolded parts often exhibit gate marks and parting line burrs, while slender fenders are prone to slight warping, necessitating standardized post-processing procedures.

Gate and burr trimming: Hydraulic shears are used to smoothly remove large cold-runner gates, while minor protrusions from hot-runner gates are precision-ground by hand. Pneumatic fine-grinding heads and fine sandpaper are used to lightly polish parting lines and corners to remove micro-flash; after dust is blown off, the housing surface is smooth and free of sharp edges. Diamond grinding heads are used to remove burrs from the high-hardness glass-fiber reinforced nylon brackets.

Annealing for stress relief: All parts requiring painting or coating must undergo annealing. ASA and ABS housings are baked at a constant 60°C for 2 hours, while ABS+PC alloy parts are baked at 70°C for 3 hours. Slow, natural cooling ensures the complete elimination of internal molding stresses, preventing cracks caused by high-temperature baking or outdoor temperature fluctuations.

Thermal shape correction: Warped fenders and side guards are secured in metal fixtures for low-temperature shaping; they are released after cooling to correct warping and ensure uniform assembly gaps across the vehicle.

Surface pretreatment: Parts destined for painting undergo electrostatic dust removal and degreasing to eliminate mold release agents and surface dust, thereby enhancing paint adhesion. Transparent PC instrument covers receive a UV-curing treatment to improve wear resistance and protect against stone chips. Small functional parts require only burr removal before proceeding to quality inspection.

V. Multi-stage Quality Inspection and Finished Product Storage

As motorcycle plastic parts are critical to both aesthetics and safety, a three-tier inspection system is implemented: first-article verification, patrol inspections every 30 minutes, and comprehensive inspection of finished products. Following mold changes, material swaps, or process adjustments, the first ten molded parts are designated as "first-article" samples; quality inspectors use calipers to measure mounting holes and snap-fit dimensions and conduct visual inspections for defects such as silver streaks, air bubbles, burn marks, sink marks, and weld lines. Sample parts undergo a 1.8-meter drop impact test, and mass production proceeds only if the housings show no cracking or shattering.

During mass production, in-process inspections focus on monitoring housing warpage, flash, and color deviation; critical assembly dimensions are re-measured every two hours to track process stability. For glass-fiber reinforced structural components, inspections specifically target defects such as exposed fibers and internal cracks. Finished products undergo a tactile inspection of all edges and corners to ensure the absence of sharp burrs; samples are subjected to UV weathering, oil immersion, and high/low-temperature cycling tests to simulate demanding outdoor riding conditions. Defective plastic parts are isolated and ground down separately; reworking or mixing them with conforming products is strictly prohibited.

Conforming body panels are individually wrapped in EPE foam and stored in sealed, light-proof cartons to prevent premature yellowing or degradation of the ASA and ABS materials caused by prolonged light exposure. Simultaneously, records of raw material batches, molding machines, and process parameters are maintained to establish a comprehensive production traceability log.

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