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Auto Vise Do's and Don'ts

Hebrewhammer8

Cast Iron
Joined
May 14, 2009
Location
Bellingham, Wa
I recently rebuilt some Schunk KSP-160 Air Actuated Vises that I bought off ebay a couple years ago. I plan on setting this up in my VF4 and use them manually actuated then possibly use them with a robot full auto.

As I'm rebuilding them I was thinking alot about what they might be good for and what they might not be good for. They are very tight still and have minimal slop.

I imagine these types of vises with 2 floating jaws would be good for first operations and not so good with softjaws for 2ndary ops? Possibly suffer from bad jaw/part lift when used with soft jaws.

Anyone care to enlighten me with Auto-Vise horror stories, misloads, scrap parts, curses and swearing? Some do's and don'ts when using auto vises loaded by hand and with automation. Thanks in advance!
 
Not much to say about the general functionality of the vises. They work. Grease them as needed or your clamping force will drop off.

Jaws can make or break the reliability of your process. I only use steel soft jaws, with big steps cut into them. I rarely get misloads, and if I do, they get caught by the probe, and I probe every part.

If I use grippers, I machine soft jaws to accommodate them, and the grippers sit a minimum of .125" high, more often .250". This is not a place to save money on material.

The weak point of a robot load is neither the robot nor the vise, but the robot gripper. They have low force and robot fingers are noodley. Parts can slip in the fingers. The rest of your system needs to be robust enough to compensate. So having a generous "landing area" for the part, along with programming that allows you to clamp/unclamp and reseat the part go a long way.

Cleaning is also very important. I find a simple airblast from the robot to be insufficient long term. I prefer that the robot exit the machine entirely when a part is unloaded, and allow the machine to run its own coolant and air blast cycles on an empty vise, before returning to reload the next part.

It's easy to load a bunch of parts successfully. It's hard to never misload a single part.
 
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We have 2 KSP-250 in our Okuma M560V. They work great. We use the machine during the day for fixture building and robot load it at night. As mentioned above be sure to grease as needed. We have a seperate PLC for control of the vise. We added capacitive sensors to detect clamp/unclamp/misload that are tied into the machines cycle stop/estop circuits. This was one of our learning curves. If the material was too warped we would get misload and not always catch it. Now if the PLC doesn't see a good clamp signal the program stops. Likewise if a part pops out during machining the machine stops. We also have a 4-20mA pneumatic transducer to allow us to control vise pressure from a common variable in the machine. We can rough at high pressure, then set the variable mid program to reduce pressure for finishing if needed.

 
Awesome Info! Thanks for the replies!

It seems anyone can buy a robot and plop it in front of a machine but where the magic lies is creating a process that is uber reliable. Many Devils in the many details!
 
Awesome Info! Thanks for the replies!

It seems anyone can buy a robot and plop it in front of a machine but where the magic lies is creating a process that is uber reliable. Many Devils in the many details!
+1. Programming robots is not all that difficult. The reliability and robustness of the cell lies in the communication of devices. I set up all my cells to have IO data shared between the machine and robot. Things like in cycle, door open, door close, alarm state, etc. I also add every sensor necessary to have robust operation and error handling. Prox switches, door switches, safety locks, laser sensors, light curtains, RFID chips, etc. This way I can capture data in the robot or PLC to help troubleshoot issues. It also allows for a more closed loop programing. You can get feedback/confirmation of every critical step of the process versus putting a dwell and hoping everything happened as you planned.
 
They're fine for second ops if they're tight. Very repeatable. When you close the door and do your wash down cycle to clean the jaws with coolant, the next thing you will need to add is really good filtering to your coolant lines.

Once you have a chip embedded in a jaw the cell will happily make dozens or hundreds of parts with the same ding in all of them otherwise before anyone notices.

Probe every part, of course.

Robot loading for first ops is trivially easy. Second ops are a lot tougher if you have tolerance or aesthetic requirements. Five sides on a first op robot loaded, and then one side on a pallet hand loaded is probably a better place to start than trying to jump straight to one and done.

*Edit* also air blast can be helpful, but it has a bad habit of kicking chips that weren't on the jaws around again.
 
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