Robot presents all 96 cavities and cuts shot inspection time by 64 percent

Custom injection molding of tight tolerance diagnostic devices, drug delivery systems and implantables · Inspection · Trade press

The job

Vision Technical Molding in Manchester, Connecticut runs a 96 cavity medical tool at under 10 second cycles, and qualifying a shot means checking a part from every cavity for dimensional accuracy and color. Doing that by hand meant an operator handling 96 small parts, identifying each cavity, and running separate dimensional, visual and weight checks, which is slow and easy to get wrong. A custom cell built into a corner of the clean room now uses a small vision guided six axis Adept robot to present a part from each cavity to a laser micrometer, a vision system and a laboratory scale. The cavity ID is read by optical character recognition and results are pushed to a central SPC system.

The shop

Headcount: not published. What is published: 28 injection presses from 28 to 330 tons running 24/7, two neighboring plants expanded from 54,000 to 81,000 square feet, and a 10,000 square foot Class 8 clean room holding all production presses.

The equipment

Small vision guided six axis Adept robot presenting parts. Keyence laser micrometer, Cognex vision system and Mettler Toledo laboratory scale as the fixed instruments. Optical character recognition for cavity identification, with data output to a central SPC system. Custom built cell. Gripper or end effector on the Adept robot: not published.

The published numbers

Inspection time: cut by 64 percent for all 96 parts from one shot, reported-by-trade-press. Tool and cycle: 96 cavities running less than 10 second cycles, reported-by-trade-press. Plant level result: cumulative efficiency improvements over a couple of years gave output capacity equal to four additional machines and three additional shifts a week, reported-by-trade-press and attributed to many changes together, not to this cell alone. Payback: not published. Cell cost: not published. Scrap or escape reduction from this cell: not published. Inspector headcount change: not published. Defects caught: not published.

Where a source did not publish a figure, this entry says so rather than guessing.

What we would check before believing it applies to you

Presenting the part to fixed instruments is usually cheaper and far more accurate than hanging a camera on the arm, because the metrology stays in a controlled fixture and the robot only needs to be repeatable rather than accurate; that is the architectural lesson worth copying. The genuinely valuable piece is reading cavity ID by OCR and pushing results into SPC, which converts inspection from a pass or fail gate into cavity level process feedback, and on a 96 cavity tool one quietly drifting cavity is exactly what ruins a lot. Before assuming 64 percent, price what your current manual check actually costs per shot, because 64 percent off an already quick check is small money, and note this cell still measures one part per cavity per shot, not every part. The article publishes no cell cost, no payback and no change in escapes, so the business case is genuinely unproven from this source; treat it as evidence the method works, not as a financial reference. Finally, the cell dates to 2011, so a shop quoting this today should get better speed and lower cost from current gauging and vision hardware.

Sources