EOAT Tips and Troubleshooting FAQs Index of Questions and Answers: Cup marks on product Adding grippers is a problem Re-working EOAT problems Insert Molding problems Wiring problems Problem: I have an injection molded part that needs to be pulled away from the lifters on each side. There is one hole on each side of the part causing to pull away. I have used several types of cups but they leave marks on the parts. Any suggestions on how to pull this part?

Please also read this article from Tim Thatcher on troubleshooting parts handling - when do-it-yourself robot tooling is not the way to go.  In the article, Tim cautions readers that assuming modular components will always fill the bill can be a costly mistake when it comes to more complex applications. So it is important to know when your molding application needs the special benefits that are available with a custom-engineered tool. READ MORE

Answer:
Based on your comments, we suggest trying other types of materials of cups like Nitril or Polyurethane and even possibly the duel durometer polyurethane cups -- those are excellent for eliminating cup marks (however they are more expensive). Also it might be best to just go with gripper fingers to secure the part.

Our sales department is going to arrange to have our local rep contact you to bring in some samples. If I can be of any further assistance please let me know.

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Problem:
“I’ve built my tool, but realize now that I need to add more grippers – which is causing me now to re-do much of what I have already built. How do I avoid this in the future?”

Answer:
It is not uncommon to want to go back to a tool and add additional gripping components, sensors or other components after running initial tests with your new tool. To avoid a complete re-design, we recommend adding flexibility into you tool – to allow for this. To start with, we recommend using an "H" shape profile design, as it allows for the greatest amount of flexibility without adding much additional weight. Using longer profiles also gives you room to easily add components later.  

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Problem:
Because we have several different kinds of robots, that use the same tools, we always run into wiring problems when moving the tool around. Switching from PNP to NPN means sending the tool back which creates downtime. Is there an easier way to solve this?

Answer:
Custom-engineered and most off the shelf tools usually come with a logic junction box, which provides built-in protection to minimize damage when changing sensor wiring (junction boxes make it easy to switch from PNP to NPN format or vice versa with a simple switch of the jumpers). This also means a tool can easily be moved from one robot to another. To move a tool from one robot to the next and from PNP to NPN – you would only need to move (1) wire on a terminal strip in the junction box to change the signal from PNP to NPN.

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Problem:
“We have a tool, that is used on several presses. But when we move it from robot to robot, we always have to re-work the tool? Why is this happening?”

Answer:
Your tool is most likely not square. Making your tool square will reduce your set-up time when you move it from robot to robot. Your Robot must be square with the press.

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Problem:
“During insert molding applications, we have problems with consistently placing the insert into the mold at the same point each time. How do we fix this?”

Answer:
Spring loaded guide pins are a must for insert applications - because you need to allow your EOAT to locate with the mold prior to reaching the point of insertion. If you have enough space, 3 points of intersection are preferred to ensure your tool is in the correct positioned. Spring loaded guide pins are also ideal for adjusting your EOAT as you will be able to easily make small and measurable adjustments to get a repeatable process.

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About The Author
Tim Thatcher is production manager at SAS Automation in Xenia, Ohio. Thatcher has been with SAS since 1998 and is in charge of production of all modular components, custom tooling, degating equipment, custom machinery, and robotic automation cells. He can be reached at (888) SAS-EOAT.