Triac 1991 tool changer problem.

regnilham · Post by **regnilham** » Mon 28 Jul , 2008 3:58 am

Hello,
This is my first post on this forum. I just purchased a like new Denford Triac ATC made in 1991(A beautiful machine). It has the built-in screen and auxillary monitor along with a 6 position tool changer. The problem comes when the tool is loaded. When the tool change is activated the holder drops out of the spindle before the changer gets into place. When the new tool is loaded into the spindle the air cylinder does not pull it up and again the tool falls out when the changer goes back to home.
The stud pull up cylinder does pull into lock position when I program a tool change but releases and does not lock when the new tool is put into place.
What should I look for?
Thanks in advance,
Charles

bradders · Post by **bradders** » Mon 28 Jul , 2008 8:32 am

The newer Machines had "Belville Washers" (A type of conical spring washer) that when mounted together forms a very strong spring that held the tool holder in position, these could need retensioning or if some have broken coud need replacing

Martin · Post by **Martin** » Mon 28 Jul , 2008 8:38 am

Hi Charles,

It may be something as simple as the arm in micro switch that is sticking or broken. Does the tool drop out before the arm is in position? There is a small micro switch on top of the slide that tells the control when the arm is fully in. You will need to remove the ATC cover to get to it.

The other point to check is if the spindle & tool changer are lining up correctly. At the start of a tool change the spindle needs to orientate to line up with the ATC. Then as the arm comes in a small amount of air is sent to the "Brower unit" (tool clamp/release cylinder) to mechanically align the spindle using a "V" formation on the shaft & on the Brower unit. It may be that your spindle is stopping in the wrong place & pushing on the "V" wrong. If the orientation is out the collar can be moved to suit.

Steve · Post by **Steve** » Mon 28 Jul , 2008 15:32 pm

Hi,

The tool release is as Martin says controlled by a Brower unit (an air presure amplifier which then compresses the spring stack releasing the drawbar and dropping the tool.

I would suggest you use the M Code index and use the M24 and M25 commands to grip and release a tool.

The Brower units can leak oil and then need adjusting. Make sure the tool releases and grips correctly.

The Mint logic should ensure the toolholder is in position before the release command is given and again it should grip the tool before the head lifts at the end of the toolchange sequence.

I think the switch that indicates the arm is in position is on the air cylinder (and probably has an LED indicator on it)

Hope this helps

Martin · Post by **Martin** » Mon 28 Jul , 2008 17:53 pm

This machine sounds as if it is a Triac ATC with a PNC3 Control (North East Electronics) & therefore may not be able to accept individual M codes for the toolchanger.

Mr Magoo · Post by **Mr Magoo** » Tue 29 Jul , 2008 0:02 am

From what I remember the ATC works like this...

The "arm In" solenoid energises, providing air to the Arm In cylinder, and also a reduced pressure to the Brauer unit. This is meant to provide enought movement at the drawbar to orientate the spindle, but not release the tool. I think this 'reduced pressure' had it's own regulator knob (in the back panel I think?).

The next step in the cycle is the "Drawbar Unclamp" solenoid energising to provide full pressure to the Brauer and so release the tool.

It sounds like this 'Reduced pressure' stage is set too high and so the Brauer is releasing the tool during the orientation stage. Try reducing this 'reduced pressure' (I hope there is a regulator for this!)

HTH

regnilham · Post by **regnilham** » Thu 31 Jul , 2008 11:24 am

Thank you for all the responses to my problem. It does have the secondary regulator and I tried different pressures with no luck. I do not have the unit connected to a computer yet and am operating it from the built-in controls (I don't know if that will make a difference). There is a key switch on the side of one of the control boxes in the back that says "Spindle lock/release".
I have tried this in both positions with no difference.
When I program the spindle speed and start the spindle it locks the tool in perfectly but as soon as I stop the spindle it falls out. When the changer puts the tool in it never actuates the clamp and when the change retracts it falls out.
This machine has not been used and looks like new so I feel it is something simple. Does anyone know how the dip switches inside the atc box should be set?
It is a Triac ATC serial EO 3926 made in June 1991. Thanks again for all your help.

Martin · Post by **Martin** » Thu 31 Jul , 2008 16:22 pm

Don`t touch the switches.

I presume you have air to the machine. The main pressure regulator needs to be set to about 6 Bar. The second one inside the box needs setting at 1.5 Bar. This is the one that aligns the spindle after orientation. I f you can`t get it working as is then connecting it a PC will make not difference at all from what I know.
The switch at the side is a manual Draw Bar release so if you turn the key then the Brower unit should activate & allow a tool to be place up the spindle. If you then release the key switch the Brower unit should release & the tool clamped in the spindle.

Post by **Denford Admin** » Fri 01 Aug , 2008 9:09 am

When the changer puts the tool in it never actuates the clamp and when the change retracts it falls out.

From the sound of this - I would guess that there is some sensor not working. I'm not sure of the logic at all, but guess that the trigger to clamp up would come after seeing the arm-in sensor on the cylinder

Try and check the operation of all the tool change sensors with a volt-meter - like you say it looks like something simple and could just be that a reed switch on the air cylinder has moved out of position

regnilham · Post by **regnilham** » Fri 01 Aug , 2008 11:15 am

I am going to do a full check on all of the switches this weekend. The keyed drawbar lock/unlock switch does nothing either. When I start the spindle the tool locks in perfectly but as soon as I stop it it falls out.
Does anyone know what kind of driver I need for this machine or will Auto cad run it via rs-232?
Thanks again for all your help,
Charles

Steve · Post by **Steve** » Fri 01 Aug , 2008 13:22 pm

Take a photo of the switches before you touch any of them otherwise you will spend months trying to find out how to put them back!

Post by **Denford Admin** » Fri 01 Aug , 2008 15:38 pm

Does anyone know what kind of driver I need for this machine or will Auto cad run it via rs-232?

There are a shed load of posts discussing this topic:
viewtopic.php?t=1107
viewtopic.php?t=882
viewtopic.php?t=709
viewtopic.php?t=511
viewtopic.php?t=352
etc...

regnilham · Post by **regnilham** » Sun 03 Aug , 2008 1:35 am

Thanks for all the great responses to my problem. I still have no solution as of yet. If I am right, pressure is applied to the drawbar cylinder and the spring washers are compressed dropping the tool holder. The new tool is inserted, the pressure is released and the new tool is locked in. Here is what is happening: When the spindle is started, pressure is applied to the drawbar and the tool drops out. As soon as the spindle is stopped the drawbar clamps tight once again. Something is out of sequence here and I just can't put my finger on it. I have pulled out the electronics drawer and checked for loose connections or anything else that looks wrong but have found nothing. I have set both regulators at the proper pressure.
One thing that bothers me is that the keyed drawbar release switch has no affect on anything. Inside of the ATC box with the electronics there are 2 green led's that stay lit and one red one that is blinking. I wonder if that is a problem.
Thanks again for all your help and maybe this will be simple to fix

Charles

Martin · Post by **Martin** » Sun 03 Aug , 2008 12:30 pm

Have you got both of the comms leads connected to the ATC control box? I remember there were 2 leads to connect to the underneath of the atc electronics box to the PNC 3 control.

What happens when you datum the machine?
Does the ATC Arm drown down & then back up as the machine is performing the Datum routine?
It may be worth removing all the tools from the carousell & the spindle & performing several toolchanger opperations to see what the problem is.

If as you say all is OK until the spindle is run look at the brower unit supply at this stage.
There should be no air going to this unit after a tool change has been performed.

regnilham · Post by **regnilham** » Mon 04 Aug , 2008 1:01 am

I took all of the covers off to see what is happening. When I start up the machine (Turn the key and push on) it comes to life and the drawbar cylinder
is activated and the tool is released (Onto a foam pad). I datum the machine and it asks if I want to datum the tool changer also. When the tool changer begins to move the drawbar pulls up to lock and the spindle rotates to the proper position. The drawbar then releases before the changer gets to the spindle. After the tool is placed and the tool changer retracts the pressure is never released and the drawbar never locks. At that point if I go to spindle control and start rotation the drawbar then retracts into the lock position. As soon as I stop the spindle the drawbar once again activates and unlocks the tool.
All connections look good and all of the other functions work fine. Are there any schematics out there for this machine?
Any ideas???
Thanks again for the help,
Charles

Martin · Post by **Martin** » Mon 04 Aug , 2008 10:21 am

Hope these help.

regnilham · Post by **regnilham** » Mon 04 Aug , 2008 21:40 pm

Thanks for the schematics Martin! They will be a great help with the diagnosis.
Charles

regnilham · Post by **regnilham** » Mon 04 Aug , 2008 22:11 pm

Thanks to the schematics provided by Martin I have solved the problem

It puzzled me why the keyed drawbar release switch did nothing when switched. After looking at the schematic and measuring the voltage across the switch (there was none) I disconnected one of the leads going to the switch and checked for continuity. The switch was CLOSED in both positions!!!
I then powered up the machine with the wire disconnected and everything works properly.
With the switch always in the release position there is no way the tool would stay put. Talk about simple fixes that take a long time to find..this was a dandy. Since this machine is like new I never would have suspected a bad switch.
Thanks to all that responded as well as Denford Machines(Who directed me here).
Now I just have to figure out how to make it run from autocad.
Thanks again,
Charles

Martin · Post by **Martin** » Tue 05 Aug , 2008 6:40 am

Well done, I guess that the Brower unit was energised all the time. No wonder the tool was dropping out.

Mr Magoo · Post by **Mr Magoo** » Tue 05 Aug , 2008 10:25 am

This sounds like the output from the ATC controller to the drawbar solenoid is permenantly on, or the keyswitch is permenantly closed (and so the drawbar is permenantly in the release position).

For safety reasons a normally closed contact of the spindle run relay is in serias with the drawbar solenoid circuit so that the drawbar can not be released with the spindle running, as soon as the spindle stops the drawbar releases!!

The drawbar release keyswitch caould be faulty. Try disconnecting one of the wires from the back of the keyswitch. THIS IS 240v SO DO THIS WITH POWER OFF AND TAPE UP THE WIRE BEFORE POWERING UP!!!

The LEDs on the ATC controller sound OK. the 2 x green are for power = OK, and the red should be flashing steady (same amount of time on and off). If it's off for a while then a few quick flashes it's indicating an error (or not datumed) - the number of flashes gives a clue to the fault (but only a clue - I don't have a manual for the ATC

)

HTH

Denford Software & Machines

Denford Software & Machines