What You Need to Know About Injection Molding Gates
Injection molding forces molten plastic toward and through a gate, an opening that lets the material enter the mold cavity. Sprues and runners allow this material to flow, but it’s the gate that controls access to where molding happens. Because the size of the gate affects the pressure of the plastic, proper gate sizing is critical.
If the gate in an injection mold is too large, molten plastic fills the cavity unevenly, and makes defects such as shrinking and weld lines more likely. If the gate is too small, short shots and high levels of residual stress at the gate may result. The shape of the gate also affects the flow and can contribute to or help minimize part defects.
In addition to size and shape, injection molding gates differ in terms of thickness. Typically, large, thick-walled plastic parts require thicker gates to accommodate a higher volume of flow. Smaller injection molded parts usually require thinner gates, but not at the expense of adequate pressure.
How Data-driven Manufacturing Unlocks Speed and Transparency during Injection Molding Process
Many of the parts we manufacture have at least one measurement that’s mission critical. Maybe the parts won’t work in an assembly unless a planned hole is within spec. Typical CAD models provide an opportunity to include specific dimensions, but what if you could tell your manufacturer early-on that dimension X is the one that makes or breaks a part? That’s where Critical-to-Quality (CTQ) comes in.
The CTQ specifications that you include in your quote and CAD model help to guide us during manufacturing, saving another critical dimension: TIME. We can often tell you if it’s possible for us to make your part before the mold is cut.
CTQ is also an important element of our digital manufacturing processes because we use these specs to evaluate initial runs of your parts. Let’s say that your parts require sample qualification or part validation. CTQ becomes even more crucial at that point because the data that flows from those initial shots can predict the future tolerances for those critical dimensions, revealing the suitability of end-use parts for a given assembly.