Experts in Automotive Injection Molding

The automotive industry is currently one of the most advanced manufacturing industries in the world. Automotive Injection moulding plastic parts are becoming increasingly popular as a way to improve safety, increase fuel efficiency, use alternative fuels, and reduce environmental effect.

That’s why engineers from major automakers come to Kaysun for help with their most difficult design difficulties, including material selection and performance, design for manufacturability, prototyping, mould design, tolerance, quality control, and more. These materials show how having a good relationship with an injection moulder is crucial for detecting and resolving errors before they become costly:

Common Automotive Molding Defects and How to Solve Them:

If the parts used contain moulding faults, they may be subject to rework, rejection, and budget-busting increases in overall cost of manufacturing. Often, these flaws are discovered after the final product evaluation, when it is too late to fix them.

Because the quality and precision of plastic automotive components can affect vehicle safety and reliability, avoiding this costly scenario is critical. When product engineers know what to look for and work with an experienced complex injection moulder, they may help prevent or correct typical moulding flaws like:


Short Shot Molding occurs when molten plastic does not completely fill the mould cavity, leaving some areas without any plastic. Because of this variability, the final product is or quickly becomes flawed.

General causes: Improper shot calibration or plasticizing capacity, early solidification of a viscous plastic, or trapped air due by improper degassing or gas venting are all possibilities.

  1. Raising the injection pressure, speed, or temperature can help with fill rate and hesitation issues.
  2. Flow constraints can be alleviated by removing frozen flow channels or redesigning the mould.
  3. Insufficient venting can be remedied by installing air vents towards the end of the affected channels.


Flow and weld lines are the result of molten plastic travelling through a mould. Flow lines are streaks, patterns, or lines that depict the plastic’s physical course before and after cooling. Weld lines indicate where plastics from different parts of the mould meet.

Flow lines are caused by changing molten plastic flow speeds and directional variations inside mould shapes, as well as changes in wall thickness or injection speeds that are too slow for uniform solidification. Weld lines form when two or more flow fronts fail to bind properly due to molten plastic partial solidification.

  • Injection moulders will alter spots where wall thicknesses, flow directions, or speed abruptly change, or put gates within the component’s thinner walls to maximise injection speeds and pressure.
  • Injection moulders will raise molten plastic temperatures, increase injection speeds, rethink the design to make it a single source flow, or move to a less viscose or low melting temperature plastic for weld lines.

The Benefits of Injection Molding for Automotive Manufacturers:

In a recent blog, we looked at how injection moulders may help minimise the cost and risk of automotive components by getting involved early in the design process.

But what about the influence of the plastic components in automobiles? What are the advantages of employing them for manufacturers?
Plastic components created by a skilled complicated injection moulder provide a particular competitive edge to automobile manufacturers by addressing four key areas:


While greater fuel efficiency is an essential, if not expected, benefit of using lighter-weight materials in vehicle construction, there are other advantages to using injection moulded plastic car components instead of metal parts. Manufacturers can include modern safety equipment, electronic systems, and emission control devices – all of which are constructed largely of plastics – to push technological advances and efficiencies to obtain a competitive advantage by lightening the burden.

Working with a skilled injection moulder to create these reduced weight plastic components is arguably best demonstrated in the electric car industry, where any weight savings correlates to improved power system efficiencies and consistency in all-electric battery range. Using injection moulded plastic components in fuel-based cars and trucks means lower carbon emissions and ready compliance with increasingly rigorous government rules.


There’s no denying that putting products to market fast can help carmakers stand out from the crowd.

Plastic car components, unlike metal parts, lend themselves to finite and sophisticated mould flow analyses prior to manufacture. Through computer-aided design and modelling, moulders alongside specialist engineers can forecast and interpret how plastics will act and react in real-world conditions, and then select materials that are appropriate for the purpose. Physical testing is not required for noise and vibration, and other critical factor testing for those components can often be decreased. Vehicles made of plastic components are proven to be reliable, and they reach the market much ahead of those made of traditional metal construction.


Expertise in Metal-to-Plastic Conversion for High-Quality, High-Performance Results:

Automotive OEMs are embracing metal-to-plastic conversion as a proven method for decreasing vehicle weight and enhancing fuel efficiency in the face of tougher federal and environmental laws. Fuel economy goals, emission standards, and operational cost savings can all be fulfilled by replacing heavy metal parts with identical but lighter-weight injection moulded plastic components that are just as robust.

Kaysun can deliver cost-effective metal-to-plastic conversion solutions for the toughest automotive engineering difficulties by utilising modern technology, best practises, and sophisticated quality control systems. The following resources illustrate the advantages of this innovative strategy and provide examples of how Kaysun assisted customers in achieving success:

Converting Metal Automotive Components to Plastic in 3 Easy Steps:

The automotive industry has been required by law to increase the average fuel economy of cars and light trucks built in the United States since 1975. The Corporate Average Fuel Economy (CAFE) requirements, which were developed in response to the Arab Oil Embargo of the mid-1970s, are still in effect today, with an emphasis on improving fuel economy, lowering greenhouse gas emissions, and saving customers money at the petrol pump.

To that aim, the National Highway Traffic Safety Administration (NHTSA) and the United States Environmental Protection Agency (EPA) have teamed up to design and release joint final CAFE compliance guidelines that apply to five-year blocks of vehicle models. It begs the question of how automotive makers will continue to fulfil CAFE criteria as legislation and automobile efficiencies evolve.


Part of the answer rests in automobile lightweighting, which is designing vehicles that are lighter in weight and, as a result, have greater fuel efficiency and handling. Injection moulded plastic components, rather than die cast metal ones, offer realistic options for reducing vehicle weight, reducing engine strain, and improving overall performance. Furthermore, fewer metal parts mean less rusting, landfill garbage, and environmental hazards.


While it may appear that swapping metal car parts for injection moulded plastic components is a straightforward process, it is actually a sophisticated engineering process. Designers must grasp the mechanical and structural distinctions between metal and plastic in order to predict how the materials will behave in real-world situations and how metal-to-plastic conversion will affect outcomes.

There are three important actions that design engineers must take to accomplish this:

Analyze the feasibility:

Finding out if your vehicle project is acceptable for metal-to-plastic conversion is the first step. This necessitates a thorough examination of the design from both a technical and economic standpoint (understanding the end-use, environmental conditions, manufacturability, and so on). Aside from the cost/return analysis, significant consideration must be given to the realistic capacity to build a suitable design and the feasibility of carrying out the conversion.

Selection and testing of materials:

The availability of 25,000 engineered plastic materials allows for practically infinite design freedom and personalization, but choice must be made carefully. To understand how the plastic will behave in real-world settings, prototypes and thorough plastics understanding are required to match the suitable material to the automotive application. In this step, injection-molding engineers evaluate the plastic’s physical and chemical properties, such as strength, flexibility, and melting and cooling characteristics.

Additional design considerations:

Even if the feasibility analysis and material choices indicate that a successful metal-to-plastic conversion is possible, launching into the project without considering every aspect of the design could be harmful. Plastics have various mechanical qualities that affect product performance in the end-user environment, therefore just swapping plastic for metal in a design rarely works. These variations, on the other hand, can be addressed by incorporating design elements such as increased wall thickness or ribs for further strength. Take some time to consider whether plastic will alleviate one problem while also causing others.

Histories of Automotive Injection Molding Parts:

The relationship between automobile OEMs and their injection moulder is critical for preventing products with design, engineering, or materials difficulties from reaching the market – and for offering OEMs a competitive edge.

Car Injection Molding Part Histories: 3 Proven Solutions to Complex Industry Challenges describes Kaysun’s unique solutions for a number of automotive manufacturers, which included:

  • To comply with a “no flash” rule on the spring-loaded inserts of a sunroof front frame, robotics, bespoke presses, and automation were used.
  • A metal belt tensioning pulley assembly was converted to plastic to minimise its weight, cost, and noise level.
  • To overcome a regularly malfunctioning heavy truck parking brake valve component, engineers used part design, process engineering, and materials understanding.

Added Value in Automotive Part Design and Material Selection:

Injection moulded plastic parts are put to a lot of work in automobile applications. The complexity of designs is rising, and tolerances as fine as.001 inches are frequently required. Temperatures, chemical exposure, and performance requirements are all extremes in harsh under-the-hood operating environments. Designs and materials must be able to withstand the test of time.

More than 25,000 resins have been developed to give specific physical properties including strength, flexibility, temperature, corrosion, and UV resistance. Kaysun engineers share their extensive understanding of material science and injection moulding to assist automobile OEMs in selecting the optimal plastic for performance and cost. This is evident when designing and producing complicated parts and components for vehicle brakes, cooling, fuel distribution, and powertrain systems.

These resources show how involving Kaysun early in the design phase leads to the most efficient design, material selection, and plastics performance:

Automotive Plastic Components Benefit from Molder Materials Expertise:

Sleek dashboards, seats, floor mats, and other automobile plastic design aspects that attract purchasers aren’t the only things that attract customers. These measures may provide some protection, but the total safety and performance of a vehicle is mostly determined by under-the-hood plastic car elements that are typically overlooked.

Nearly 40 distinct types of basic plastics and polymers are utilised in automobiles, which is not surprising given that plastic accounts for roughly one-third of a vehicle’s 30,000 parts.

Despite the enormous numbers, four polymers account for almost 70% of the material used in automobile plastic components: polypropylene (PP), polyurethane (PU), polyamide (PA), and polyvinyl chloride (PVC) (PVC).

1 When it comes to automotive plastic design, utilising any or all of them is most useful when done in partnership with a reliable injection moulding partner.

An skilled injection molder’s material knowledge and knowledge of the automotive sector are priceless. They make sure that the plastic components in automobiles and the vehicles in which they’re installed meet National Highway Traffic Safety Administration (NHTSA) regulations.

How involving moulders in the design process lowers the cost and risk of automotive parts:

While the end goal of injection moulded automotive components is manufacturability, quality, and performance, design engineers must carefully consider every aspect of the development process to get there. This includes how the injection moulding process affects the overall fit, function, performance, and safety of those critical use components.

Establishing a relationship with a reputable injection moulder and involving them early in the design process is a critical first step toward meeting manufacturability objectives. In fact, hiring a skilled injection moulder before finalising prints is a good idea. The plastics expertise of the moulder will aid in steering the component design away from potential pitfalls that would otherwise add cost and risk. This is especially important when converting a die-cast metal part to injection-molded plastic.


Molders have a solid grasp of how polymers behave during the moulding process, which they have learned via rigorous testing and analysis, as well as the use of techniques such as design for manufacturability studies. To identify potential difficulties with the part, this test uses finite design analysis and mould flow simulations. The earlier a moulder does a design for manufacturability study, the less costly changes and delays will occur throughout the tooling and production phases.

A design for manufacturability study boosts profit possibilities in addition to saving costs. The time saved by working out the problems in a design prior to purchase order approval equates to a shorter time to market and a distinct competitive advantage.


Failure of an automotive component can have disastrous effects. Recalls, warranty claims, and litigation have a significant and long-term New brand impact, in addition to putting end users in danger.

Risk minimization is a priority and the emphasis of a manufacturer-molder collaboration in every level of automotive component design and manufacture. By bringing in a moulder with experience in sophisticated injection moulding during discussions about specific design requirements – such as parts that outlast warranty durations, for example – you can take use of their knowledge of resins and thermoplastic behaviours well before production. Identifying and employing materials with certain features like as heat and chemical resistance or greater force strength allows manufacturers to create vehicle components that break down infrequently, reducing the chance of harm or warranty claims.

In terms of cost and risk reduction, having a moulder involved in the design phase and throughout the process is a useful asset for automobile manufacturers in general.