A practical breakdown of injection mold architecture, covering frame selection, core/cavity integration, and ejection systems with real-world engineering data.

When laying out an injection mold, the frame (模架) is the skeleton that dictates everything downstream. For standard 2-plate molds, we typically start with a 25–35% larger frame than the part’s projected area to allow for adequate runner placement and cooling channel routing. In the 24 diagrams referenced, the key is not just the A/B plate thickness—which for a 150-ton machine often lands at 60–80 mm—but also the guide pillar and bushing clearance. I always specify a 0.02–0.03 mm interference fit for the guide pins to prevent flash, and I add a 5° lead-in chamfer on the bushing to avoid galling during high-cycle operations. The diagrams emphasize that the sprue bushing’s spherical radius must match the machine nozzle (typically R15 or R20), otherwise you get drool or pressure loss, which directly affects packing density.

Moving into core and cavity details, the 24 diagrams highlight three critical zones: the parting line, the side-action locks, and the ejector pin layout. For a part with a 2.5° draft angle on vertical walls, I calculate the required ejection force using a coefficient of friction of 0.15–0.2 for P20 steel against ABS; that gives roughly 12–15 kN for a 200×150 mm surface. The diagrams show that placing ejector pins at 20–25 mm spacing along the rib base prevents local stress whitening. Also, for deep ribs (over 8 mm), I add a 0.5–0.7° taper per side and a 0.4 mm radius at the root—this avoids weld lines and reduces the chance of sink marks. The cooling circuit in the diagrams uses a baffle design for the core, with 8 mm diameter channels and a 3 mm gap between the baffle and the core wall, achieving a Reynolds number above 4,000 for turbulent flow.

Finally, the ejection system in the 24 diagrams is not just about pins—it includes early ejector return and limit switches for safety. For a mold with 16 ejector pins, I balance the return springs with a preload of 30% of the total stroke, which prevents the plate from bouncing on high-speed cycles. The diagrams also show a micro-switch that triggers at 10 mm before full ejector stroke, which is crucial for automated pick-and-place robots. If you are sourcing molds or need to validate your frame and ejection layout against these real-world parameters, visit MoldWorld (www.moldw.com) for a comprehensive directory of mold suppliers, tooling standards, and engineering calculators that match the exact scenarios shown in these diagrams.