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Automate machining operation with a robot

surfit

Plastic
Joined
Apr 23, 2008
Location
ventura ca usa
I currently machine billet Impellers on a Haas VF-3 with a TRT-160 Trunion. The impellers cycle time is 2 hrs and we only work an eight hour shift. I priced a TRT-160-2 That has two "B" axis's they are $35,000. This would net two impellers at night, The machine only has one spindle so there is no saving on per part time. I want to look into automating it with a robot that can change parts instead of purchasing the TRT 160-2, that would net eight more parts at night. I could google robotics however I would like some input if someone here has any experiance with this type of operation,
Thanks.
 
You will end up spending much more than the trunnion cost to automate...

You should be able to find a used robot cheap, but then the list goes on...

You will then need to do the following which all require money and sometimes lots of it.

-Robot end effector
-Automated Workholding (hydro of some sort)
-Hydrualic's into trunnion / rotary couplings
-Infeed and Outfeed staging for raw/finished parts
-Robot Interface for Control
-various safety sensors
-Auto Door for Machine
-Cell Guarding
-Unattended Process Considerations (Development = Time)
-and a slew of other small though not insignificant items I can't think of!

Then you need to consider how long you will be making these for, and if the job will morph into more jobs at which point don't you think it might be cheaper to buy a second machine and hire a second shift guy which would essentially Quadruple your current output, but would significantly increase your flexibility and throughput capability.


Just looking at both sides of my $.02. Though I can't begin to know your business strategy or current picture so I don't know if the second option is feasible for you.



Husker
 
This is VERY doable, however you will need some investment.

I just started a new system up today - it's on a lathe, but I've done plenty of mills too.

I will only list the things you will need that you can't make.
You will need a robot interface for the Haas, no idea what that costs.

You will need 2 grippers, figure $700-$1000 each - Load / Unload - highly suggest Schunk for grippers.
You will need some automatic clamping mechanism. You will need clamp / unclamp feedback.
You may (probably will) need a device on the table to "seat" the part in the fixture so you can let go with the robot before it clamps - you do not want robot loading to influence your part quality.
You need a robot - appropriately sized - I suggest Kawasaki.
(Robots are rated by max payload, this includes the grippers, end effector hardware and the workpieces it's carrying.
You need something to pick raw parts from and something to put finished parts on - a table with fixtures will work for this low volume of parts.
You need guarding.....and the guarding HAS to include a safety door switch.

As Husker noted, you will have more money in this than another 4th when you are done. However, you will be putting out 8 more parts a day and no additional operator required. You will have to figure the ROI based on that.
 
You don't necessarily need a robot to load a CNC. If there is one size billet being loaded into the machine you may be able to get away with "hard" automation using pnuematic slides and the such. It will be much less expensive than a robot but you won't have much in the way of flexibility and you can create a nightmare if you go too cheap by not allowing for flexibility where you need it. Robots quickly pay for themselves because of the inherent flexibility. Reprogram for changes instead of adjusting mechanical stops (or ripping out & rebuilding) for a "hard" loader.

Even with a controller to operate the loader you will need to interface with the CNC through the CNC's I/O. An M code in the CNC will turn on an I/O to call the parts loading routine and often an input is used as well to signal that the load is complete and the CNC can continue with the program. Additional I/O is often an option on a CNC so you will need to see if you have some available. I had to use the I/O for an automatic door opener (the I/O was available but the automatic door wasn't installed) to call for the loading cycle on one loader integration project.

Lights out running can be difficult because if anything goes wrong (and it will) things get ugly really fast.

Look at a company like Parts Loaders • Toellner Systems, Inc. Parts Automation for example (no affiliation). You may be better off just training a "parts loader" to load for every cycle and do some other manual labor (deburring, mopping) the rest of the night.

Cheers
 
I'm sure robotic have come a long way since I programmed/ran them (1988ish), but,
IMHO, You can pay a warm body to stand there and change parts for a HELL of a lot less than what an automation nightmare will cost you.

Unless of course you are electrically inclined and have time on your hands.
have fun
i_r_
 
Actually I_R_, the cost of our robots and the associated automation to install is equal to or less than the yearly salary + bennies of 1 worker. That ROI works out _very_ quickly if you are running 3 shifts.
 
Only thing i will add is you need to consider tool life and have enough pockets in the tool changer to be able to swap cutters during the night.
 
When working on the design think ahead a little.
We put a setup like you are describing in a shop, 2 months later the work load quadrupled, they wound getting a new mill and putting it opposite the old one so the 'bot could service both. They could do this because they had a large 'bot.

The billets were on a roller conveyor with some crowding features, the done parts went out on a cheap belt conveyor.

The work holding was a hydraulic vise with machined soft jaws.

The 'bot had 2 end effectors...one for loading and one for unloading.

This was a 2 operation part, they ran 24 hours of the first op, changed the 'bot effector and ran the second op.

IIRC it was around $100k all said and done.

One last thing, look at palletizing robots, you probably don't need a 6 axis bot, this can save some dough.
 
In theory you already have a robot, the machine itself. Make a loader/unloader that mounts on a tool holder and make a rack to the side in the machine to hold new blanks and to place finished parts. All you'd have to do is get some hydraulic work holding. I'm retarded though so take that for what its worth.
 
In theory you already have a robot, the machine itself. Make a loader/unloader that mounts on a tool holder and make a rack to the side in the machine to hold new blanks and to place finished parts. All you'd have to do is get some hydraulic work holding. I'm retarded though so take that for what its worth.

Turning a tool holder into a gripper is more chalenging than it appears. Most grippers have 2 air hoses and 2 proximity switches for open and close. Gripper mechanisms on tool holders are usually air open using the air in the spindle and spring return to close. This type of gripper also has no proximity switch to verify open and close which in automation means driving blind. Although you can use a tool set probe to verify part present.
If you make a rack inside the machine it gets covered in chips so now you are trying to load a part covered in chips. Also the spindle has to be able to reach the rack so it has to be within the work envelope of the machine.
Hydraulic work holding requires a rotary union. Not a big deal but changeover can be challenging.
I believe the correct term is mentally challenged.
 
Hydraulic work holding requires a rotary union.
Hydraulic would be a challenge, a mechanical activated gripper without air or hydraulic could work just fine.
May need to make two grippers if the finished dia is way smaller than the raw material, some ol'school creativity could be a big increase in through put.
Will need some way to determine if the "load" or "unload" part is actually out of they gripper.
 
At IMTS in 2010 I saw an Erowa display, and one of the things they had was a "hive" holding some number of fixture plates, which could swap those plates into the attached machine.

And I remember being struck at how relatively low cost it was compared to what I expected, and relatively simple. But you now know everything I know about it.
Robot Systems - EROWA AG


I don' t know if it could mount parts on your B-axis trunnion or not.

I would guess it could hold many of your parts, like 24 or some number like that. (Up to 96 for the smallest size if memory serves.)

BUT - it's not as flexible as a robot. It requires that every blank have some kind of prework so it can be held by a plate, you need N plates they are not free, etc. But it might be a more practical solution.

It also seemed to have a simpler safety profile - you don't have a big arm swinging around, so the amount of fencing/guarding around the cell would be less? (Consult appropriate experts.)
 
$$$-wise, it's mostly dependent on your kinematic requirements. What's the weight of the billet and the pick and place swing, that will determine your robot size.

We're on our 7th FANUC 6-axis, 10kg install, and they run typically $140-175K with the programming and our customized vacuum end effectors.
 








 
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