Choosing The Right Injection Molding Resins For Your Part

Landing the perfect injection-molded part is never a walk in the park – often times, ensuring success starts right from material selection to process optimization. Even after a proper design and production, achieving high quality finish can be evasive. One of the most important factors in injection molding, is therefore, the selection of your resin. Resin selection is crucial to both manufacturing and finish. This is because choosing the right resin can help you achieve the right functionality and properties for your part. The material melting and cooling temperatures can also make or break the molding process. Finally, some resins are simply better suited for some cosmetic attributes that others. Now that we have highlighted the essence of getting it right from the start, here’s a quick run through of what you need to consider in picking the best resins for your injection-molded parts.

Start with part geometry 
You will need to evaluate the design of your project against the injection molding process and anticipate where design challenges may occur. It is important to understand that certain geometries are more difficult to achieve with injection molding. In order to avoid issues like warpage, shrinkage and other design issues, consider the ease of moldability of your selected resin and how it would perform in achieving the desired shape, wall thickness or part size.

What is the goal of the part?
The right resin is one that fits into the goal and purpose of your part. Because resin characteristics like strength, rigidity, chemical, electrical and impact resistance all flow into the properties of the molded part, you will need to match your resin to the desired properties of your part. If your part is to be part of a bigger assembly, consider how the material works well with other materials in.

In what environment will the part be used? 
Ask yourself what the likely conditions and environment that your part is going to function before selecting your resin material. This will enable you identify the attributes and engineering of the part to function optimally in such environment. 

Consider if your part will be exposed to harsh corrosive chemicals, high temperatures, pressure, extreme climate, creep, fatigue, electricity, heat, radiation and force. The answers to all the questions you come up in this stage will help you narrow in on the ideal resin. Also, factor in the tolerances and dimensional stability in some of these environments, the electrical ratings and required approvals for your part to be passed and considered appropriate. 

Consider costs 
Cost is typically a function of the production process. In choosing the right injection molding resins, make an estimate of the cost per unit for different type of material options. Next, pit these cost prices against the potential selling prices and calculate your margins. Depending on your results, you may choose to go for materials with lesser qualities if the end-use is simply for prototyping and display. 

The volume of the part to be manufactured can also drive or lower cost. In some instances, you will have to determine the most important characteristics and have a trade-off somewhere between cost and functionality when selecting your resin.

What type of finish are you looking to have? 
The finish or cosmetic appearance of the final part is also a function of the resin selected and used in its production. As we have noted earlier, some resins are easier to decorate and finish that others. Certain resins also have great texture and colour pigments that make them visually appealing and aesthetically pleasant. 

Consider how your desired colour, texture, decoration and the need for logos or markings resonate with your choice of resin. This will not only help you have a shorter product manufacturing cycle, it will also help you save money on post-production finishing services

First Part Injection Molding Services in China
FirstPart offers excellent quality, plastic injection molding services for a wide array of plastic part projects in China. We also offer low-volume manufacturing that serve small quantities from 50 to 10000 parts for small and medium scale establishments. Away from low-volume manufacturing, all our factories boast of an always-running mass production capacity for CNC, 3D printing and Injection molding services.

Our engineers are always available to advice on the best processes, materials and design optimization to ensure cost-savings, quick turnaround and the production of parts that are 100 percent defect and issue free. Click here to request a free quote now and submit your design for a free evaluation and contact us on how to get started on your next projects.