![\"injection](\"https:\/\/junruims.com\/wp-content\/uploads\/2026\/08\/\u6a21\u51771.png\")
<\/figure>\n\n\n\nKey Injection Mold Technical Terms You Should Know<\/h2>\n\n\n\n
1. Moldability.<\/p>\n\n\n\n
When reviewing drawings with manufacturers, being familiar with these injection mold technical terms lets you quickly catch potential moldability risks.Simply put, moldability refers to the ability of a product design to be successfully formed using the mold; it is a critical prerequisite that must be confirmed before mold commissioning begins.<\/p>\n\n\n\n
Many companies approach manufacturers with finished product drawings only to be told, \u201cThe moldability is poor; the design needs to be revised.\u201d This is because the product design contains issues such as uneven wall thickness or excessive undercuts, making it impossible to demold or mold the part successfully.<\/p>\n\n\n\n
For companies, moldability directly determines whether a product design can be realized, as well as the cost and difficulty of mold development.<\/p>\n\n\n\n
Designs with good moldability result in simpler mold structures, lower mold-making costs, and higher trial mold success rates; conversely, poor moldability not only increases the difficulty of mold design but may also lead to repeated trial mold failures, incurring additional costs.<\/p>\n\n\n\n
In day-to-day communication, if a manufacturer mentions \u201cinsufficient moldability,\u201d it means the product drawings need to be optimized\u2014for example, by adjusting wall thickness, reducing undercuts, or adding fillets.<\/p>\n\n\n\n
2. Shrinkage Rate.<\/p>\n\n\n\n
Shrinkage rate is an inherent property of plastic materials. It refers to the percentage by which the product\u2019s dimensions shrink relative to the mold cavity dimensions after the molten plastic cools and solidifies.<\/p>\n\n\n\n
Although this term may seem technical, it directly affects the precision of mold design\u2014mold designers must enlarge the mold cavity dimensions based on the material\u2019s shrinkage rate to ensure that the dimensions of the molded product meet design requirements.<\/p>\n\n\n\n
For example, if a consumer product is designed to be 100 mm in size and the PP material used has a shrinkage rate of 2%, the mold cavity must be designed to be 102 mm; otherwise, the molded product will shrink and fail to meet dimensional specifications.<\/p>\n\n\n\n
If one does not understand shrinkage rate and blindly requires the manufacturer to design the mold according to the product drawing dimensions, it will inevitably lead to dimensional deviations in the product, rendering it unusable.<\/p>\n\n\n\n 3. Tolerances.<\/p>\n\n\n\n Tolerance refers to the permissible range of dimensional errors for a product or mold; it is a core indicator for measuring mold precision and product quality, commonly expressed as \u201c\u00b1value.\u201d<\/p>\n\n\n\n Before mold production begins, the company must clearly define the product\u2019s tolerance requirements. The mold manufacturer will then determine the mold\u2019s machining precision based on these requirements. The stricter the tolerance requirements, the higher the difficulty and cost of mold machining.<\/p>\n\n\n\n Without a proper understanding of tolerances, companies may either blindly pursue excessively high precision, thereby increasing mold-making costs, or overlook tolerance requirements, resulting in excessive dimensional deviations in the molded products that fail to meet usage requirements.<\/p>\n\n\n\n 4. Mold Life<\/p>\n\n\n\n Mold life refers to the number of times a mold can produce qualified products normally and is commonly expressed in \u201cmold cycles.\u201d<\/p>\n\n\n\n Mold life primarily depends on mold materials, machining precision, and routine maintenance. The longer the mold life, the lower the mold cost per product.<\/p>\n\n\n\n When accepting the mold, verify the service life promised by the manufacturer to avoid increased production costs later on due to excessive mold wear.<\/p>\n\n\n\n 5. Mold Flow Analysis<\/p>\n\n\n\n Mold flow analysis is a critical step in mold design and prior to trial runs. It involves using specialized software to simulate the filling, cooling, and shrinkage processes of the plastic melt within the mold cavity, thereby identifying design flaws in advance and optimizing the design.<\/p>\n\n\n\n Many buyers overlook the value of these injection mold technical terms and ignore the importance of mold flow analysis.<\/p>\n\n\n\n Mold flow analysis effectively reduces the risk of trial mold failures, lowers mold repair costs, and shortens the mold development cycle. If the manufacturer states that \u201cmold flow analysis has been performed,\u201d it indicates that the mold design has been validated through simulation and can effectively prevent common molding defects.<\/p>\n\n\n\n 6. Cavities and Cores.<\/p>\n\n\n\n Cavities and cores are the core components of a mold, together forming the molding space for the product. Simply put, \u201cthe cavity forms the outer surface of the product, while the core forms the inner surface.\u201d<\/p>\n\n\n\n For example, in a plastic cup, the part of the mold that forms the outer wall of the cup is the cavity, while the part that forms the inner wall and bottom of the cup is the core.<\/p>\n\n\n\n The machining precision of the cavity and core directly determines the product\u2019s surface finish and dimensional accuracy. If the cavity surface has scratches, the outer wall of the molded product will have defects; if the core dimensions are out of tolerance, the inner wall dimensions of the product will fail to meet specifications.<\/p>\n\n\n\n 7. Trial Molding.<\/p>\n\n\n\n Mold trial involves mounting the designed and machined mold onto an injection molding machine, injecting molten plastic, molding a sample, and verifying whether the mold design and machining meet requirements. It is an indispensable inspection step in the mold development process.<\/p>\n\n\n\n The primary purpose of trial molding is to identify issues and modify the mold; this process typically requires 1\u20133 trials until a qualified sample is produced.<\/p>\n\n\n\n After trial molding, the manufacturer will issue a trial molding report, which includes the trial process, sample condition, identified issues, and proposed modifications. Understanding the meaning of \u201ctrial molding\u201d enables better coordination with the manufacturer to confirm the mold\u2019s compliance.<\/p>\n\n\n\n 8. Mold modification.<\/p>\n\n\n\n Mold modification is the process of modifying and optimizing the mold after trial molding based on issues identified during the trial. It is a necessary step to ensure the mold meets specifications. Common issues requiring modification include product shrinkage, short shots, product deformation, and difficulty in demolding.<\/p>\n\n\n\n The precision and efficiency of mold modification directly impact the mold production cycle and costs. Without a clear understanding of \u201cmold modification,\u201d you may misinterpret the manufacturer\u2019s progress or even reject necessary modification steps, resulting in the mold being unable to enter mass production.<\/p>\n\n\n\n 9. Surface Treatment.<\/p>\n\n\n\n Surface treatment is the process of processing the mold cavity surface to give the molded product a specific appearance. Common surface treatment methods include polishing, sandblasting, and texturing.<\/p>\n\n\n\n The method of surface treatment must be determined based on the product\u2019s appearance requirements. Understanding this term allows you to communicate your product\u2019s appearance needs to the manufacturer more precisely.<\/p>\n\n\n\n 10. Mold Maintenance.<\/p>\n\n\n\n Mold maintenance refers to the cleaning, lubrication, inspection, and repair of molds during mass production. The purpose is to extend the mold\u2019s service life, ensure its proper operation, and prevent production interruptions caused by mold failures.<\/p>\n\n\n\n Common mold maintenance tasks include: regularly cleaning residual plastic from the cavity and core surfaces; regularly lubricating the ejection and guide systems; and promptly replacing worn components such as ejector pins and O-rings.<\/p>\n\n\n\n Understanding the importance of \u201cmold maintenance\u201d enables better mold management during mass production and reduces losses caused by mold failures.<\/p>\n\n\n\n For those responsible for liaising with mold manufacturers, mastering these core injection mold technical terms will help you communicate more smoothly with them, clearly articulate your requirements, accurately assess mold quality, avoid detours and unnecessary expenses, and make the mold-making process more efficient and hassle-free.<\/p>\n\n\n\n![\"\"](\"https:\/\/junruims.com\/wp-content\/uploads\/2026\/08\/\u6a21\u51772.png\")
<\/figure>\n\n\n\n![\"\"](\"https:\/\/junruims.com\/wp-content\/uploads\/2026\/08\/\u6a21\u51773.png\")
<\/figure>\n\n\n\n