CNC Machine tending

[serview]

Hi Folks,
I would like to share a video of my progress with a UR 10E Cobot for machine tending.
My goal has been to machine sets of my standard product parts in small quantity batches with automation using my 3 axis Doosan DN Solutions VMC and a Cobot.
I have learned a lot from the practical machinist website and wanted to share back to the community.
We have had a lot of challenges, but have made progress and are running a machine tending application with a Cobot with dual end effector now.
I am using:

• Doosan DNM 5700 VMC
• Orange vises (Thanks Eric!)
• Rapid Design Solutions Vise Opener
• UR 10E Cobot
• SICK safety scanner
• Zimmer Grippers
• Caron Engineering MiConnect software to sequence the operation and control the CNC and Cobot
• Lang fan for chip clearing

Here is a link to the video

I appreciate the community here, and wish to share my progress.
Some challenges I wish to discuss are issues in part loading with a Cobot into a vise with parallels and a X axis stop, and error proofing of the load

Thanks for watching!
Steve

 

[Ox]

Every vid I see of machine tending is just painfully slow.

MTB's up each other to light speed rapids (OOOH! / AAAH!) and if we turn the rapids down to 50% we have Mr. King breathin' down our necks, and then we all run out and buy a sloth to tend it.
I don't have one (currently) so I'm just outside looking in, but I just don't git it....

Not picking on YOU!
It's the whole market it seems....

Just getting it going is a major hurdle for sure, and I am truly glad for you.


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Think Snow Eh!
Ox

 

[Seesecurity]

Every vid I see of machine tending is just painfully slow.

MTB's up each other to light speed rapids (OOOH! / AAAH!) and if we turn the rapids down to 50% we have Mr. King breathin' down our necks, and then we all run out and buy a sloth to tend it.
I don't have one (currently) so I'm just outside looking in, but I just don't git it....

Not picking on YOU!
It's the whole market it seems....

Just getting it going is a major hurdle for sure, and I am truly glad for you.


-------------------

Think Snow Eh!
Ox

But, that sloth will turn up every day, doesn't need toilet/lunch/smoke/chat/cut my finger breaks, won't put the part in upside down/wrong way round, won't bitch and moan to the other guys in the shop and doesn't come knocking on your door for a pay rise every 3 months...

 

[Ox]

I understand, but I have a chum with a pair of Motoman's down for the last few weeks that might dissagree with part of your "Pro" list.

The inflatuation only lasts so long, and then the wedding's over.


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Think Snow Eh!
Ox

 

[memphisjed]

But, that sloth will turn up every day, doesn't need toilet/lunch/smoke/chat/cut my finger breaks, won't put the part in upside down/wrong way round, won't bitch and moan to the other guys in the shop and doesn't come knocking on your door for a pay rise every 3 months...

Panasonic arm on sick days here....
They just ask for tech once a year- which cost more than all the raises.

 

[YoDoug]

Panasonic arm on sick days here....
They just ask for tech once a year- which cost more than all the raises.

We have 8 ABB robots here. The oldest is 5 years old the newest 2 are 1 year old. They run 24/7 machine tending, although our load cycles are only 20-30 seconds out of an average 10 min machine cycle so the usage is not that high. We have not lost one day of downtime due to the ABB's.

 

[Ox]

We have 8 ABB robots here. The oldest is 5 years old the newest 2 are 1 year old. They run 24/7 machine tending, although our load cycles are only 20-30 seconds out of an average 10 min machine cycle so the usage is not that high. We have not lost one day of downtime due to the ABB's.

Well, my chum has come to the conclussion that they must have taken a spike, as he had 3 machines down, and 2 of them were bad power supplies, and the third had scrambled brains. The 3rd machine was not a robot. It likely was NOT a Motoman problem, and the bots that are of issue here are 25 yrs old. He has very good luck with his bots.


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Think Snow Eh!
Ox

 

[YoDoug]

Generally machine tending robots have such little motion time compared to the machining operations that they last a long time. The biggest issues I have seen are from coolant contamination in non IP67 rated robots.

 

[Ox]

His are mostly welders.
One runs a stamping operation by it'self. (impressive!)

He doesn't have any bots tending mills/lathes at this time.
They don't doo a lot of machining.


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Think Snow Eh!
Ox

 

[memphisjed]

Ours holds a plasma torch, makes a cut- asks if you like the cut, sure. Doesn’t make a cut a continues on like it did.

 

[Matt@RFR]

Some challenges I wish to discuss are issues in part loading with a Cobot into a vise with parallels and a X axis stop, and error proofing of the load

Seems to me your next step should be probing and dedicated fixtures, even if that means a simple set of step jaws to replace your parallels. Parallels even held in with magnets or whatever are a huge liability here.

We don't have robots, but still have automated as much as possible with probing: For op1 like you show in the video, with probing you don't need a work stop at all. Place part, probe two places in Z to check for a bad load and probe in for X to update the work offset and check for a short or long blank. You could even probe the vise jaws to check that they actually closed if your vises don't have sensors yet.

 

[Matt@RFR]

Every vid I see of machine tending is just painfully slow.

Looks like a 34 second door-to-door time in the video. How long would a human take in your mind? And how long would that time be if you averaged every change over after an 8 hour shift? I bet it's more than 34 seconds.

Just because some meat bag is flailing around moving all fast and throwing shit everywhere, doesn't mean he's being efficient.

 

[Ox]

I git that.

But we use G0 to git close in cycle.
We don't typically use G1 F100. for the approach.

But in most all tending apps, I always see a lack of anything remotely close to G0.
Maybe there is some reason for that?
Are we gunna flip the part out of the jaws if we flip too fast?

Even on Mr. King's fancy Brother set-up, the bot there - while maybe faster than this guy's here, was still very slow in my mind.
And Mr. King is all about his rapids!

Maybe I'm missing sumpthing?
Maybe these don't transition well from G0 to G1?

And in the case of this thread, this fella is sporting a CO-bot, which precludes that it is typically slow to begin with, and I understand that as well. But how many caged animals doo we see that run the same?

I'm not of the mind that I need 2500 IPM rapids, but I doo appreciate that most of my stuff doesn't max out at 400 anymore as well.


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Think Snow Eh!
Ox

 

[Digital Factory]

Nice work!

Aside from round-the-clock operation, another nice thing about robots is the short delay between M30 and the robot getting to work, i.e. none. Makes up for the "slowness", which actually isn't even slow.

It rarely pays to sprint in a marathon.

 

[Digital Factory]

But in most all tending apps, I always see a lack of anything remotely close to G0.
Maybe there is some reason for that?
Are we gunna flip the part out of the jaws if we flip too fast?

Actually, yes. Robot grippers tend to clamp with a few hundred pounds of force rather than the few thousand we're used to with a vise. It's quite easy to pull a part out the robot fingers manually.

 

[Matt@RFR]

I git that.

But we use G0 to git close in cycle.
We don't typically use G1 F100. for the approach.

I'm with you there. It's painfully slow to watch, but then the math calms my nerves back to their standard frayed ends.

For this particular video, I believe this robot is running in 'cobot' mode, meaning the arm is unguarded (no cage), so movements are throttled by default.

 

[DavidScott]

I always thought the UR cobots were slow until I saw a video of them sorting packaging at warp speed, they actually can move pretty fast. What gets me about the ops setup is how big the mill is for those little parts.

 

[david n]

Tender bots always appear painfully slow..................but I guess slow and steady wins the race??.............

 

[mhajicek]

Seems to me another approach would be to have two pallets with high density workholding, maybe a few dozen parts per pallet.

 

[YoDoug]

With parts that small and a VMC table that big you could skip the cobot and use a tool holder mounted coolant/air actuated gripper to load the vise from a parts que on the other side of the table.