Injection Molding Industry Terminology

We switched from polystyrene to ABS to improve impact strength; ABS dries quickly but still needs moisture control; The OEM spec calls for UL 94 HB ABS.

Put the texture on the A-side for appearance; Ejector pins live on the B-side; The A/B alignment was off, causing mismatch.

Warpage increased after we moved to a semi-crystalline grade; Amorphous materials tolerate sharper corners; Gate location strategy changes with crystallinity.

Increase back pressure to eliminate color streaks; Excessive back pressure is raising melt temperature; We set 5 bar back pressure for this PP grade.

Add vents near the end of fill to prevent burns; Lowering injection speed reduced burn marks; Burn marks appeared at the rib tips due to gas trap.

We moved from 1+1 family to 8-cavity to increase output; Unbalanced fill between cavities caused weight variation; Higher cavitation lowers piece price but increases tooling cost.

This part needs about 120 tons of clamp force; Inadequate tonnage caused flash on the perimeter; We sized the press for 4 tons per square inch of projected area.

Converting to a hot runner eliminated runner waste; Cold runner length is driving our cycle time; We grind the cold runners back into the process at 20%.

Gauge R&R must be complete before freezing the control plan; The control plan calls for hourly weight checks; Add the gate vestige dimension as a special characteristic in the control plan.

Optimizing waterlines cut cooling time by 20%; Semi-crystalline resins typically need longer cooling; Thicker ribs increased our cooling time unnecessarily.

We need Cpk ≥ 1.33 on the boss diameter; Tooling changes improved Cpk from 0.8 to 1.4; Cp is high but Cpk is low, indicating the process is off-center.

Keep a 3–5 mm cushion to maintain pack pressure; Zero cushion caused short shots; The cushion drifted, indicating a check ring issue.

Reducing cycle time from 30s to 24s improved OEE; Hot runner adoption shaved 3s off cycle time; Cooling dominated our cycle time on this thick-wall part.

We used Decoupled II to stabilize part weights; Establish the viscosity curve before setting V/P transfer; Decoupled settings reduced variation across cavities.

DFM review flagged insufficient draft on the ribs; We changed wall transitions to meet DFM guidelines; Early DFM saved us a costly tool change.

Our DOE showed that velocity had the largest effect on flash; We ran a 2^3 DOE on temp, speed, and pack time; DOE cut trials from weeks to days.

Lack of draft caused scuffing during ejection; We added 2° draft to texture B-3 surfaces; Draft adjustments avoided undercut tooling.

Increase PET drying time to hit ≤ 0.02% moisture; Moisture analyzer readings were out of spec; Poor drying led to bubbles and brittleness.

Add an ejector pin under the boss to prevent sticking; Pin witness marks must be hidden from the A-surface; Sequential ejection solved deformation.

FAI report must match the latest rev of the drawing; We failed FAI due to out-of-tolerance flatness; Customer signed off after FAI with a minor waiver.

Reducing pack pressure eliminated flash; Worn shutoffs were causing flash near the hinge; Higher tonnage and venting minimized flash.

Moldflow predicted a weld line at the clip; Cooling analysis showed a hotspot under the rib; We used simulation to balance the runner system.

Move the gate to reduce knit lines; A valve gate would improve cosmetic performance; Gate freeze time is limiting pack effectiveness.

The flatness callout is 0.1 mm relative to A|B|C; Add a draft note without changing the datum scheme; GD&T clarifies the true position on the boss pattern.

We must demold below Tg to hold dimensions; PC’s Tg explains why it deforms under heat; Raise mold temp to approach Tg for better surface replication.

The hot runner cut material cost by 15%; We used valve gates to improve balance in the hot half; Heater failure in the hot runner caused short shots.

Nylon is hygroscopic—dry to 0.2% moisture; Splay was traced to wet PC; We installed desiccant dryers for all hygroscopic materials.

Velocity-limited fill reduced burn marks; We hit pressure limit causing short shots; Tune velocity profile to maintain a consistent fill time.

The brass insert warped—preheat before molding; We designed fixturing to locate inserts repeatably; Insert molding cut assembly steps in half.

IQ confirms the press and tooling are installed correctly; OQ established process windows; PQ proved the process is capable at nominal settings.

Relocate the gate to shift the weld line; Strength at the knit line failed impact testing; Higher mold temperature improved knit line appearance.

A 20:1 L/D screw struggles with high-rate mixing; Higher L/D helped disperse colorant; L/D limits our maximum shot recovery rate.

We chose a higher MFI PP for thin-wall filling; MFI differs from actual process viscosity; Lot-to-lot MFI variation impacted fill time.

The 16-cavity tool needs precise runner balance; Multi-cavity increased throughput 8x; Family-to-single-cavity split solved imbalance.

Overmold adhesion failed without a primer; We designed shutoffs for two-shot overmolding; Hard/soft overmold improved grip and sealing.

Increase hold pressure to hit the weight target; Gate freeze time defines the useful hold duration; Longer hold reduced sink but added stress.

Shift the parting line to hide it on the non-cosmetic face; Poor parting line fit caused flash; Add vents along the parting line near end-of-fill.

Customer requires Level 3 PPAP; Submit 300-piece capability and PSW for PPAP; We updated the PPAP after the resin change.

Use PVT data to set packing pressure; The PVT curve explains post-mold shrink; Simulation used PVT to predict warpage.

Limit regrind to 15% for appearance parts; Excess regrind increased black specks; Separate and track regrind by resin and color.

Reduce barrel size to shorten residence time; Color shift indicates over-residence; Adjust back pressure and screw speed to control residence time.

Raising melt temp solved the short shot; The flow front stalled at the thin rib; Short shots disappeared after balancing the runner.

Account for 1.5% shrink on this PP; Uneven wall thickness drove differential shrinkage; Gate location influences directional shrink.

Increase hold pressure to reduce sink; Core out the boss to thin the section; Moving the gate closer diminished sink marks.

Start X-bar/R charts on part weight; SPC signaled a shift after the resin lot change; We tightened the process window based on SPC data.

Make the snap width steel safe by +0.2 mm; We opened steel to tune the fit; Steel-safe callouts were noted on the drawing.

Set V/P at 95% cavity filled to avoid flash; Bad transfer caused weight variation; Pressure-limited transfer stabilized the process.

Add vents at the end-of-fill to fix burns; Dirty vents caused splay and burn marks; We used micro-vents along the parting line.

Run a viscosity curve every material lot; The curve shifted right, indicating higher viscosity; We selected a 0.8–1.2 s fill time from the curve.

Balanced cooling reduced warpage by 30%; Gate relocation improved warpage; We added ribs and adjusted fiber orientation to control warpage.