Air Drill issues

[r_jones]

So I received my air drill and in fine Shop bot fashion the manual is about useless. With that in mind I have some questions.

1. The unit drills and plunges when I switch on input 5 manually but doesn't do either when I run a file??
2. Shouldn't input 5 run the drill and 6 plunge or should 5 do both?

[Gary Campbell]

Ron...
I have put an air drill together using the instructions, they are not perfect, but are workable. Just in case you dont have the full set here is a link: http://www.shopbottools.com/files/SBDocs/SBG00330071031PRSalphaAirDrill.pdf

1) the drill should plunge and drill with output 5 as you describe. What post Processor have you selected for your drilling? If using partworks it should be one that says "PRS Drill Head 1" or something similar. You must also select tool #31 when you toolpath. This should be done for you if you follow the directions on page 14 of the Linked PDF above.

2) As shipped, the OEM drills work correctly as you describe. Should you not have enough air to run the drill like that, Nat Wheatley has the part numbers for a retrofit kit I speced to allow anopther output to operate the drill motor.
Gary

[r_jones]

Gary,
Thanks for the additional info! Unfortunately I have received the "new" board from SB and it seems they don't have a diagram that reflects the new accessory board and my original PRS control board. So far no dice.

I am using the SB PRS drill processor with tool number 31 and nothing. The odd thing here is that the file will show output 5 is on but there's nothing, no plunging or drill movement.

Once I have this worked out I am very interested making the mod to reduce air consumption, one thing at a time I guess

[Gary Campbell]

Ron...
Can you post a copy of the file? If Output 5 works the drill, all of the electromechanical items are working. My guess is the problem is in the postP or something odd in the file. You can also email it to my address in my profile.
Gary

[r_jones]

You are the bomb sir!! I will shoot that over to you shortly!

[nat_wheatley]

Ron,

I just stumbled across this thread, not sure why I hadn't seen it earlier. Here's a link to the drill modification:

http://www.talkshopbot.com/forum/showthread.php?t=5434&highlight=compressor

Let me know if you have any questions when you get to this stage.

Nat

[vassilm]

Hi.
There is something I do not understand about the Air Drill. Why is it that the plunging is supposed to be done with the Z-steper motor? Why not plunge with the pneumatic cylinder of the Air Drill itself? To make it clearer, my routine would be:
1. jog to position in XY with drill retracted and off
2. activate output 5 - drill is extended and on (no movement of the stepper motors, i.e. no MZ movement) - thus the hole is drilled
3. deactivate output 5 - drill is retracted and off
4. jog to next hole
5. repeat sequence...
What would be wrong with such an approach and why is it not the one used by Shopbot? My thinking is that it is much faster to move along Z by means of the pneumatic cylinder than having to wait for the motor to move up and down. And second, this way there is no problem with air consumption which was described previously in the forum:
http://www.talkshopbot.com/forum/showthread.php?t=5434
Vassil

[wberminio]

Ron

I had just updated my SP control software to latest version.
My drill worked manually,but not when I ran file.
Called Shopbot
Check post proc. line 38.Mine needed an apostrophe before the statement.

[nat_wheatley]

Vassilm,

The main issue I see with the set up that you've outlined, is that there would be no way to regulate the plunge speed for your drilling. Different materials require different drilling speeds. I think the rate that the plunge cylinder travels would be much too fast for most applications.

I'm also not sure the drill motor would have time to come up to speed before meeting the material, particularly where the plunge cylinder would be drawing air at the same time that the drill motor was coming on.

Nat

[vassilm]

Hi Nat,
Thanks for the reply.
I think you can regulate the plunge speed by regulating the air pressure to the pneumatics of the drill.
If you use the stepper motor for plunging what speeds would you typically use for different materials (melamine faced chipboard, MDF, solid wood)?
One problem I used to have with my approach was that when turning the drill off it is still in the hole and thespring in the pneumatic cylinder was not strong enough to retract the drill. But I solved this by adding an extra stronger spring to the outside of the air drill.
Vassil

[Gary Campbell]

Vassil...
In general, what Nat says is correct, I will add to it. I bought my first PRS before ShopBot produced a drill for it, and I did a great amount of experimenting in this area. I have used many different options for both plunging and switching, wont say I'm an expert, but have drilled tens of thousands of holes testing electric, hand held inline (like the SB) and the ARO industrial programmable drills. I have recorded video of most different actions. Here is one of the ARO drills working as you desribe: http://www.youtube.com/user/Islaww1#p/u/5/Tr5TvVV5YNE

Although this worked, it requires the drill to traverse its entire stroke for each hole. This is usually 3-4 inches. The plunge speed can be adjusted somewhat with flow controls, but it usually takes a good number of tests to get good results. In order to insure that the machine "stays" in position till the hole is completely drilled, I added prox switches to the bottom of the stroke. When slow plunge speeds are required, it is not efficient to plunge 3-4" to drill 1/4" deep holes. This is the only option for drill control that I am aware of that will work with Gcode. Other than those drills that run continuously during a drill cycle, this configuration uses the most air. Air is used to plunge, retract and drill for each hole.


In 2009 ShopBot software developers added some "trickery" to the code that triggers an output during a plunge only move. This allowed users of the SB drill to add the dual control as Nat refers to above and cut air consumtion considerably. It also decreased cycle times. Here is a video that was taken just after this new code was implemented. It shows the drill plunged for the complete drilling file, and the enhanced code turning on the drill, only during the down drill move. http://www.youtube.com/user/Islaww1#p/u/7/QmYlwc4Cmlw


This advancement has shown to use the least air, and allow full software control of the plunge speed. This may be the best feature of the PRS style drill over the PRT. I have used plunge speeds ranging from .125 to over 4 inches per second. This range of adjustment is not avalable using flow controls on plunge cylinders. This is one of those areas where we SB users have an advantage over Gcode machines.

Hope this clarifies those drill actions.

[Gary Campbell]

Vassil...
You and I were posting at the same time. I can give some info for your questions to Nat.

Most sheetgoods I have tested use plunge speeds from 1 to 2.5 ips or 60 to 150 ipm. I dont have good numbers for Melamine. Often as slow as .125 ips for aluminum.

If you use a single solenoid, 5 port valve for your plunge control and a dual rather than single action cylinder, the retract will have the same power as the stroke. This gives that additional advantage that retract speed can be controlled by flow control valves also.

[vassilm]

Gary,
As always, your answers are very thorough. Thank you very much. It is now much clearer.
As right now I do not have a second solenoid installed and I cannot control plunge and spinning separately, what air consumption am I to expect if I use the method where the drill is on all the time and it moves along Z with the stepper motor? And is it a viable way of using the drill on a continuous basis if I don't have this second solenoid?
Vassil

[Gary Campbell]

Vassil...
I do not know what your drill consumes, so I cannot even venture a guess. I can say, based on the experience of owners of the SB PRS drill, that the cfm seemed to be more then 25cfm when used continuous. Intermitent use enabled by addition of the 2nd solenoid and the new control options lowered this to under 10 cfm.

For example, my IR SSE-5 5hp 60 gal compressor puts out around 15cfm @ 90 psi. You can see that those of us with similar sized compressors went from a non working to a working situation.

All of the different setups are viable, just different. And each has a different air cfm requirement.

[vassilm]

I was wondering, do you think I can put a regular drill bit in the spindle (I mean one that would normally be used in the Air Drill)? And if yes, at what rpm speeds should I spin it for drilling?
I am trying to have 2 different drilling diameters.
Vassil

[bleeth]

There is not a problem putting a drill bit in your spindle. I just did that recently for a load of holes in aluminum. I spun the spindle at around 1750 similar to the speed I would have from my Milwaukee hand drill but faster than a drill press. Feed was pretty slow since it was aluminum and I used peck drilling to keep the flutes clear. An air drill usually spins quite a bit faster than a Milwaukee, in fact many other drill motors do. I would start there, but if it were wood use a more normal plunge rate. .5ips-1.5ips

[Gary Campbell]

Vassil...
Now that I have an ATC all bits are placed in the spindle. For my cabinet related boring I use Carbide tipped Boring Machine bits. Sizes 3mm to 20mm. RPM from 2500 to 6000. Feeds from .5 ips to 4ips. All use a 10mm collet.

I have tried both regular and brad point bits and wasnt as happy with the results.

[vassilm]

Again. Thanks a lot. This discussion was very helpful.
Vassil.