• Part design guidelines on double injection molding

    In this article, we will show you from three aspects to be taken into consideration when designing plastic parts for double injection molding so we can save our customers time and money in the long run.   Mechanical structure     Surface Contact Adhesion is depending on materials compatibility, process temperatures, surface contact area, molding sequence and designing of mechanical interlock systems. If design not allows enough contact surface area, Tooling can make up like Make-up 1 : Increase expose surface byincreasingroughness. Make-up 2 : Employ interlock Wall Thickness Utilize 2nd shot to get more uniform wallthickness  Reinforce the 1st  and 2nd shot(transparent) by structure design such as “H” section etc. Thin but high rib in 2nd short. First shot thicker than 2nd shot. 2nd shot should be as thin as possiblewhen flow and weld line is not a issue. In MP case, 1st shot 0.6mm, 2nd shot 0.6mm was made Avoid sharpcorner Make…

    Mold design January 10, 2020
  • How to define number of cavities in a plastic injection mold?

    When it comes to cavity number for a plastic injection mold, there is a lot to be considered by injection molder though usually the number of cavities is decided by the customer.  Please note the following:   The most important thing to consider is the size of the part and how complext. Does the part have a lot of slides,lifters, core pulls etc. Size of press that the mold is going to run in, how many tons in the press rated for, what’s the platen size, and what’s the shot size. What is total quantity of the part? all you must consider delivery time on the parts. If you have a tight just in time delivery schedule that will also determine the amount of cavities needed to support the timing. What is the target cycle time? How is the resin going to be distributed within the mold? surface runner, insulated…

    Mold making January 7, 2020
  • How to Troubleshoot Flash Defect on Two Shot Injection Molding 

    What is flash in two shot injection molding? Description  2nd material penetrating between 1st material and its cavity. It is observed frequently where 1st material shrinkage is big and cooling time for 1  material is too long. It is mainly due to too fast shrinking of 1st material.   How to trouble shoot the flash? 1.Optimizing holding pressure & Cooling time to get min shrinking of 1st material till before 2nd shot molding. 2.Select less shrinkage rate material for 1st shot. 3.Changing design as preventive action. We’ve spent the past 15 years accumulating rich practical experience in solving the flash of two-shot injection molding. HS Mold has the design, engineering, and in-house tooling capabilities you need to streamline your project 2k injection molding project from conception to production.              

    Injection molding process January 3, 2020
  • What is two shot injection molding?

    Two shot injection Molding, also called over-molding multi- component or 2K Injection molding, employs separate injection points for each material in a sequential process. After initial portion material or component is molded, the core half of the mold holding the part is rotated to another, cavity where a second resin is injected.  Below is a simple diagram to illustrate theory of twin shot injection molding.     There are 3 types of two shot injection molding.   Co-Injection Molding: Sequential injection into the same core / One material as the skin , one as the core of the products. Materials can be from the same type and/or be different internal /core.     Multi-Color Injection Molding: Part are same plastic material but usually different Material bond each other, but clearly separated.     § Multi-Material Injection Molding: Partmade of different plastic materials. Materialbond but usually clearly separated. Twin shop injection molding is easy to understand, but it’s…

    Mold making December 21, 2019


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