Secondary Equipment

EOAT (End-Of-Arm Tooling) is the tool mounted on the wrist of an industrial robot that handles freshly molded parts: removing them from the mold, positioning them, separating the sprue, stacking or delivering them to secondary operations. It is the mechanical interface between the robot and the part. ## Role of EOAT in injection molding The EOAT enters the mold during opening, picks up the part with suction cups or grippers, removes the sprue if any, and places the part on a conveyor or work station. Its design defines the extraction time —typically 0.5 to 3 s— and therefore a significant chunk of total cycle time. ## Common components - Base plate with the robot-wrist interface - Vacuum suction cups (for flat, smooth surfaces) - Pneumatic or electric grippers (for parts without suction surfaces) - Presence sensors and vacuum switches - Sprue cutters - Pneumatic system with control valves ## Types of EOAT - Off-the-shelf for simple parts - Custom aluminum or 3D-printed for complex geometries - Modular reconfigurable (30×30 mm profile systems) - Multi-part for family or multi-cavity molds ## Design considerations and common issues Excessive weight (slows the robot), interference with the mold, vacuum loss on porous surfaces, gripper wear failures, and misalignment when returning to the mold. Mitigated with path simulation, redundant sensing and preventive maintenance.

A molded part is the finished plastic component produced by injection molding, its shape formed by the mold cavity. It is the deliverable of the whole process — one part per cavity, per shot. ## Part vs shot - Molded part: a single finished component (its mass is the part weight, see cavity weight). - shot: everything injected in one molding cycle — all parts plus runners and sprue. A 4-cavity mold yields 4 molded parts per shot. ## What defines a good part A molded part is judged against the print on several axes: - Dimensions: within tolerance, allowing for contraction (shrinkage) and dimensional stability over time. - Weight: stable shot-to-shot — the simplest health check of the process. - Appearance: free of sink, flash, short shots, splay, weld lines and burns. - Mechanical / functional: strength, fit and function as designed. A part that fails any of these becomes scrap. ## From mold to inspection After cooling, the part is freed by part ejection and removed by free-fall, robot or operator, then it may be degated, inspected and packed. ## Related terms - See also: cavity, shot, molding cycle, part ejection, dimensional stability ## What is a molded part in injection molding? It is the finished plastic component shaped by the mold cavity, produced one per cavity each shot, and judged on dimensions, weight, appearance and function. ## What is the difference between a molded part and a shot? A molded part is one finished component; a shot is everything injected in a cycle — all the parts plus the runners and sprue. ## How is molded-part quality checked? By dimensions against tolerance, stable part weight, cosmetic appearance (no sink, flash or short shots) and mechanical/functional performance; failures are scrapped.

Part ejection is the final stage of the molding cycle, where the cooled molded part is pushed out of the open mold so the next shot can run. It happens after the clamp opens and the part has solidified enough to hold its shape. ## How parts are ejected The ejector system pushes the part off the cores: - Ejector pins: the most common — round pins behind the part. - Ejector sleeves / blades: for bosses and ribs. - Stripper plate / ring: pushes on a large rim to avoid pin marks on cosmetic parts. - Air ejection: a puff of air breaks the vacuum on thin, deep parts. ## How the part leaves the cell - Free-fall: the part drops onto a conveyor or bin — typical in an automatic cycle. - Robot / eoat end of arm tool: picks and places the part for handling, gating or inspection. - Manual: an operator removes it (semi-automatic). ## Why it matters Eject too early (before enough cooling time) and the warm part distorts, sticks or shows ejector-pin push marks; too late and you waste cycle time. Proper draft, polish and ejector layout let parts release cleanly without drag marks, white stress or warpage. ## Related terms - See also: molding cycle, molded part, cooling time, eoat end of arm tool, automatic cycle ## What is part ejection in injection molding? It is the final cycle stage where the cooled part is pushed out of the open mold by ejector pins, sleeves, a stripper plate or air, then removed by free-fall, robot or by hand. ## What causes ejector pin marks? Ejecting before the part is cool enough, too few or too small ejector pins, or insufficient draft — the pins push into a still-soft surface and leave witness marks. ## How is part ejection automated? Either by free-fall onto a conveyor in a fully automatic cycle, or by a robot with end-of-arm tooling that picks the part for downstream handling.

Peripheral equipment (auxiliary equipment) is everything around the injection molding machine that feeds it, conditions the material, controls temperature and handles parts — as opposed to the press itself. Getting the periphery right is often what separates a stable, automated cell from one that fights moisture, color and scrap problems all day. ## What counts as peripheral equipment - Material drying & conveying: dryers, hopper loaders, vacuum conveying and central material systems. - Dosing & blending: gravimetric or volumetric dosers and blenders for masterbatch, additives and regrind. - Temperature control: mold temperature control units (thermolators/TCUs) and chillers that hold the coolant setpoint. - Part & runner handling: robots and eoat end of arm tool, conveyors, sprue pickers, degating and vision-inspection stations. - Size reduction: beside-the-press granulators that turn runners and rejects into regrind. ## Why it matters The press only melts and injects; much of the quality is made — or lost — at the periphery. Wet resin from a poor dryer causes splay and weak parts; an unstable temperature unit drifts dimensions and cycle; a robot with EOAT turns a semi-auto job into a lights-out cell. It is the broader secondary equipment that makes a molding cell productive. ## Related terms - See also: dryer, hopper, eoat end of arm tool, regrind, secondary equipment ## What is peripheral equipment in injection molding? It is the auxiliary equipment around the machine — dryers, conveying, dosers/blenders, mold temperature units, chillers, robots/EOAT and granulators — that conditions material, controls temperature and handles parts. ## What is the difference between peripheral and auxiliary equipment? They mean the same thing: machinery that supports the molding machine rather than doing the molding. "Peripheral" and "auxiliary" are used interchangeably. ## Why is peripheral equipment important? Because melt quality, color, dimensional stability and automation all depend on it — drying, dosing, temperature control and part handling happen outside the press.