[mflux_gamblej]

I thought that this maybe should go on a new thread. It started as me complaining about QC30 wrecking up my mill a bit. I guess as QC30 gets old and worn out, you need to be looking out for chatter and finally tools coming out of the spindle under high torque.

Anyway! I built a power draw bar to replace the QC30 setup. Here's where I'm at now. I should have it on the mill in a day or two.

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As promised - here's some pictures (a nice youtube video!) of my power drawbar build. I'll post some more when its actually installed on the mill. I'm excited. I should have done this long ago..

Power Draw Bar: Arduino, SMC Manifold, and Impact Wrench Rebuild - YouTube

[mwoodard]

Nice. I'll be following this and am interested in seeing how you will install it on the machine. I image you will be using some type of standoffs.

[mflux_gamblej]

I am getting very close now. I've been hung up for a couple of days on an 'add-on' feature. I want the buttons to be disabled when the spindle is on. Or rather, when the spindle power enable is on. Anytime you hit the cycle start button the spindle fan turns on and the power to the spindle drive is applied. This includes when ref'ing the machine on mains power up, and of course when you start a cycle or want to execute any MDI command.

There is a circuit which turns off the spindle brake when you press the cycle start button. The brake is mechanical in that it is a fail to close brake. Springs shove the brake on when there is no power, to turn the brake off, you have to energize a big electromagnet to pull the brake up and off of the spindle's brake rotor. My intention is to use this circuit to build in a power enable feature for my power drawbar. So, when the brake is on (power not applied to the electromagnet) the power drawbar buttons would be enabled.

This isn't strictly necessary, but on the off chance that someone would try and run the power drawbar when the machine is running, it'd be better if it said No.

I am (trying) to use an optocoupler to separate the unregulated 24V, which is more like 35V sometimes since I run on an RPC, from my microcontroller which can only handle 5V and a tiny amount of current. It also needs to reverse the logic in that when the brake circuit has no power, by drawbar power is enabled. That shouldn't be an issue since I can just program whatever state I want using the microcontroller. However, I am having difficulty getting the optocoupler to turn on when the brake is off. It's like the electromagnet is drawing enough current that even if I don't put a resistor on the input LED of the optocoupler that no current will flow through the device and it just goes into the electromagnet only (these are in parallel).

I'll be spending my memorial day figuring out what to do

[mflux_gamblej]

Update on Power Drawbar Setup:

I do have the setup installed on my machine. I haven't solved a problem with the power enable circuit. The unregulated 24V DC is very noisy and varies quite a bit. At any rate, I plan to install a relay instead of the optoisolator that I have on there right now. The relay should be less sensitive to noise. That will fix the power enable circuit issue I believe.

In the mean time I have it working enough to test it out. It turns out that the 5/32" air lines are not nearly large enough to provide enough air volume to get any torque out of the impact gun. To solve this problem I ordered some large diameter ports that I'll put on the air solenoids / manifold. I will obviously then uprate the diameter of the tubing (to 3/8"). This should solve that problem too.

Another issue that I ran into was that the tool in and tool out buttons that I installed crowded the control panel on the front of the mill too much. So I built a new control panel. I think it looks pretty slick. Picture is attached!

I also managed to replace the little lamps that go inside the 'spindle off' and 'axis DC power enabled' switches. This kind of repair makes be feel like I'm getting my machine back to it's former glory. It's nice to see the lights light up as intended. The bulbs I got are radioshack p/n 272-1119 '#1819 bayonet-base lamp'. To get to the lamps you need to take off the back of the push button using a small flat blade screwdriver. Then you pull the back off and inside are the small lamps. Just put the new one in and screw the push button back together.

Attachment 187376



For those of you who are not familiar with the Interact 1 Mk2, here is a picture of the original faceplate

[mflux_gamblej]

I finally finished the install of my power drawbar. I had some trouble with troubleshooting the power enable circuit - which ended up being controlled by a cheap relay instead of the fancier optocoupler circuit that I wanted to use. Additionally, the 5/32" air lines were not big enough to power the impact wrench well. So I had to find the SMC part number for replacement ports. I got some 5/16" (0.25" ID) stuff and now its running great. Here's a video of the finished product:

Power Drawbar: Installed on Bridgeport Interact 1 Mk 2 - YouTube