How do you grab a plastic part and package it, leaving no evidence you even touched it? In the small world of micro molding (MM), mold design is certainly a challenge, but handling the parts themselves can be even more challenging at times, especially at high speeds. At times, these parts seemingly violate the laws of physics and gravity.
Accumold Part Wranglers
Early in my career at Accumold, I was called to our engineering conference room as the team was debating solutions for an unexpected part handling challenge. The team was troubleshooting part handling of a manufacturing process for a new part measuring 0.015”x 0.031” long, standing 0.0118” tall. The problem? The parts ending up scattered all over the floor and machine, despite a 0.015″ total eject distance.
I didn’t have a sensor that could count or see those very tiny parts back then, but mechanically sweeping the part off two 0.005” eject pins wasn’t any less imperative. Therefore, I ended up designing a mini arm to reach into the mold, pull the part, gently release it through a tube and capture it in a vessel with vacuum passing thru. The mechanical design of our end of arm tooling (EOAT) solution was our verification function. Why is verification so crucial?
Part Removal Verification Is A BIG Deal
As I explain to students in numerous educational programs Accumold assists with, “In MM robotics, it’s one thing to grab a part, but verifying you did is much more important.a” When we teach new automation employees thru our Accumold Scholar program at Accumold and students about our molds, I always explain why verification is important.
Our molds are made of hardened steel, but because of their size and intricate detail, a mold can be damaged if we don’t remove runners & parts each and every time the mold closes. Succesful verification ensures part accuracy.
When I started at Accumold 16 yrs ago, they only had a couple sprue picker units. These robotic arms are extremely basic. Today, we touch almost all the parts we make with SCARA, Cartesian robots, or in-house specialty built units.
This technology isn’t cheap, but the data speaks for itself. Time after time, our automation department and robots have saved us and our customers money & time. More than that though, our home-grown technology, has also enabled us to do things in the micro mold world that are not done anywhere else on this planet. Our automation and robotic designs give us an upper hand not just in the USA, but in the world marketplace.
In many cases, our team is asked to remove parts from a mold where the part is the same size as the ejector pin. Using strategies in the design phase with the part shape in the mold, allows us to strip the part off the eject pin but hold onto the side of part and place in gel packs.
Our team does this all on very short timelines. We don’t get to see the mold run first, then design to that effect. When the mold designers start their work, Automation starts also.
When Gravity Isn’t Enough
Most all of the engineering-grade materials we inject at Accumold must be dried to -40 dew point. Therefore, when that part comes out of the mold it has very little ability to ground itself out to the robot EOAT.
Many times, we have to touch the part with certified medical plastic materials that act as insulators to correct this. Consider what happens to that part when you move it quickly thru another air mass (robot movement) with different properties. It becomes a static generator!
Some laws of physics like electrostatic induction, the triboelectric effect, and Lenz Law can make a very small part not go where we need it to go, specifically, downward to the earth via gravity. Understanding if the part has been dropped, and knowing it’s where it should be is vital. Handing off parts to the next process forces to use many different types of verification. Utilizing cameras and fiber sensors sometimes necessary to verify if that 0.040” diameter part is on the EOAT and then removed from the EOAT at packaging.
Accumold’s Automation Department
Today at Accumold, our automation department has grown and has gone from simple EOAT projects to a central part of our process. We manage machine design & build of MM platforms that have sequences of inserting loading off feeder bowls, molding, and we inspect molded parts.
This can even include verifying insert gold plating is intact on four sides plus top of part gold inspection, 2nd robot assemblies of cover parts off different feeder bowl, camera inspection of assembly, and placing parts in pocket tape with camera tracking. All finished parts are lot-controlled with data back to enterprise system controls
Here are a few of our standard tasks:
- Standard Pick & Place Small Mold & Micro Mold
- Part Separation of multi-cavity molds
- Insert Molding with 0.0003” Max Clearances of Insert to Mold Fit
- Part Assemble Of Different Parts- When the 2nd Part Is Ejected- Press Fit
- Tray Packaging
- Inserting Glass components in main substrate part with rubber overmold on 2nd inject press
- Spread Sheet Camera Inspection down to micro tolerances & color detection
- Leadframe molding with incoming & outgoing inspection plus part singulation, pre-bending of leadframe
- See our micro mold design guidelines
Building robust automation systems to handle very small parts for our customers is our daily work. Many times, our finished part tolerances are of smaller portion than the Insert we just robotically loaded in a mold.
Bring us your challenging part designs. We’ll bring the brains and years of experience to your project.
Ron Baiotto is a Mechanical Automation Engineer II at Accumold. He holds a degree in tool & die from DMACC and has 30+ years experience in the injection molding industry.