Injection Molding Project Checklist

Got an exciting project development that involves injection molding? Have you been searching for where to start? Today, we share our top things to consider and consequently, our Firstpart injection molding checklist before requesting for a quote on your new project! 

First, the basics 

Before you can understand the requirements in the checklist, you need to have a basic understanding of how injection molding works. Injection molding involves the processing of plastic pellets (resins) inside a mold under high temperature and pressure. 

The mold is an injection mold tool that is the size and geometry of the part you want to make. The plastic resins are heated and crushed until they become molten, and ran into the mold. The hot plastic material flows through the mold and takes its shape. It is then allowed to cool and solidify. The solid part is the ejected and processed further. 

Injection Molding Checklist  

1. Mold type 

There are up to 5 different mold types by classification of the U.S Society of Plastic Engineers (SPE). The first thing to check off your list involves determining what type of mold your project requires. The class or type of mold plays a significant role on the landing cost of your part. The appropriate mold price is also dependent on the desired end-use of your part and the volume of parts to be made. 

Mold classifications range from 101 to 105. Here’s a brief overview of each class by volume: 

• 101 – Extremely high volume with cycles greater 1m parts

• 102 – Medium to high volume with cycles lesser or equal to 1m parts

• 103 – Medium volume for cycles no more than 500,000 parts

• 104 – Low volume molds with cycles no more than 100,000 parts 

• 105 – Prototype only mold with volumes not exceeding 500 prototypes

2. Resin type 

After the mold type has been specified according to the desired volume, the next step is to determine what resin will be used in making your part. The resin selection stage is very crucial to different proponents of the project. There are thousands of resins available on the market today, and getting it right or wrong can make or break your project. Resin types affect the functional, physical and chemical properties of the finished part. They also impact cost. 

Choose resin based on the critical properties required for your part. Resins have different properties including varying strength, abrasion resistance, cost, durability, elasticity, impact absorption and more. 

3. Surface finish

Surface finish determination is crucial in both pre and post-processing. The type of surface finish for your part can range from purely cosmetic to functional. Cosmetic surface finishes are meant for aesthetics and beauty, while functional finishes can deliver properties like abrasion-resistance, increased strength, durability and more. 

Depending on what your part/prototype will do, you may or mayn’t need to splash a lot of cash on the surface finish. Injection molded parts can be polished to gloss, matte or mirror-like finishes. They may also be media-blasted, painted, spray painted, etc. 

4. Mold flow & analysis 

Once you have determined the class of mold to be used and the resin material, your project team can conduct a mold flow analysis. The mold flow and analysis helps to plan the injection molding process parameters to ensure that the mold cavities will be optimally filled, gates well stationed, and consequently, parts well manufactured.

5. Budget 

Mold classification and product purpose will help you check off your budget requirements. The higher the parts to be made from the mold, the more expensive the mold. Other cost-contributing factors include design simplicity or complexity, the presence of complex features and overall project leadtime. Projects with tighter deadlines will understandably attract more cost. 

6. ISO certification 

ISO certifications benchmark quality levels and can be a great indicator of excellence. Before contracting a job to an injection molding company in China, ensure that they have the appropriate ISOs. The most common ISOs are the 900, 14001, 22000 and 13485. 

First Part Injection Molding Services in China

FirstPart offers high quality, thermoplastic injection molding service for all your plastic part projects in China. We also offer low-volume manufacturing that serve small quantities from 50 to 10000 parts and produce for mass production. 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.