Simple Drilling

[Tool-n-Around]

I’ve either forgotten or never knew how to properly use the drill MOP, or maybe I have a problem with my post processor. I use the grbl machine plug in and grbl post processor one of the members here helped provided to me which solved another problemon my machine controller.

I’ve read the documentation, searched and read a number of threads on the forum in the tutorial section and others, and still no joy. When I attempt to execute the MOP on my machine. It immediately fails and returns an error message that “unused gcode exists” and fails in alarm. I havent figured out what I'm doing to produce the error.

In the attached file, I first tried to use the drill MOP with a point list and canned cycle. Now the documentation says this uses either a G81, G82, or G83. Does that just depend upon which of the features you have selected in the MOP as to which gcode is written? Or by not selecting some of the features is it writing multiples to the gcode?

I tried spiral drilling and same thing. I was still using the point list but specified a diameter. Did it need a circular Primitive ID instead of the point list?

I didn’t really want to use spiral, because it was going to be a .125” hole and the smallest bottom cutting end mill I had was .125”. The part being machined was a rather precious aluminum casting and I figured the center of the end mill plunging without movement would instantly gum up and I was too scared to be experimenting and break off a mill in the casting.
I ended up having to place circles on the point list centers and used a point cutter I had to drill centers, but told CB the cutter was and endmill the size of the hole and made the hole .0001” larger so it would accept it (the only enabled MOP in the attached file). Then I manually drilled the blind and tapped the holes in the centers.

I need to make a mating cover plate for the casting from .25” aluminum plate, which is easier to come by then the casting, so I’m feeling somewhat more courageous. I’d like to use a .125” drill and then follow with a spiral drill to slightly enlarge the holes as clearance holes for the screws and have it come off the machine complete.

Drilling is too common of a function for me not to understand how to use it, so if you guys could sort me out, I’d appreciate it.

Best,
Kelly

[lloydsp]

You have to set up a drilling MOp with a 'peck distance'.  That will determine how far the drill moves down per 'stroke'.

With your clearance plane at 0.1 and your stock surface all the way down at -0.247, that's a LOT of pecks per hole, but it works with G83, and only creates the 19 G83 drilling MOps, when I tried it.

However, I'm wondering why the stock surface is so low?  Usually, we'd set the stock surface (that surface at which drilling is to begin) to be zero, and the retract height far-enough up to clear any walls or boundaries on the material (say 0.375).  If you did that, then the target depth for the drilling MOp would be only -0.062.

Hmm.... that seems like an awfully shallow hole!  Did you intend to tap those holes in order to put in screws?  That wouldn't work with 1/8" holes.  If so, there's a basic error in your thinking about the ultimate target depth.

Lloyd

[Tool-n-Around]

You have to set up a drilling MOp with a 'peck distance'.  That will determine how far the drill moves down per 'stroke'. With your clearance plane at 0.1 and your stock surface all the way down at -0.247, that's a LOT of pecks per hole, but it works with G83, and only creates the 19 G83 drilling MOps, when I tried it.

Thanks Lloyd I'll try that on the cover plate. For a .25" thick plate the clearance and machine limitations described below won't come into play, but I will note the clearance plane, peck and retract height settings.

However, I'm wondering why the stock surface is so low?  Usually, we'd set the stock surface (that surface at which drilling is to begin) to be zero, and the retract height far-enough up to clear any walls or boundaries on the material (say 0.375).  If you did that, then the target depth for the drilling MOp would be only -0.062.

This is because I machining and intake manifold casting and the height of the casting was at limit (practically speaking beyond) of my machine envelop. The wheels on the x-axis, ever so slightly bush the top side of the casting....that's how close, so no additinal room for clearance under gantry. Even with the shortest .25" end mill I had, I barely had enough z travel and retract height to clear the casting with the end mill (maybe .050" to spare) thus the low clearance setting..........but I got it done and it came out very nicely considering what I was asking of this machine of rather modest capabilities......consequently I was very conservative with my stock removal, and was brushing on cutting fluid ahead of the cutter, but the pucker factor was still rather high. I had previously made a foam pattern and cast that from scratch so it was a rather precious casting.

Hmm.... that seems like an awfully shallow hole!  Did you intend to tap those holes in order to put in screws?  That wouldn't work with 1/8" holes.  If so, there's a basic error in your thinking about the ultimate target depth.

That's because I had already decided against attempting to drill to depth for the above clearance reasons because, I didn't have enough clearance or z travel for a drill bit, and also because apparently I didn't know what I was doing because of the error, so I was attempting to use the drill MOP to just install drill points for manual drilling and tapping after the fact, thus drill point depth only. Picture attached below might give you a better idea of what I was up against.

Thanks.

Best,
Kelly

[dh42]

Hello

GRBL do not handle G81, G82 and G83 naturally. If you're using the right post processor, CamBam can simulate the G81 (simple drill) and G82 (simple drill + delay at the bottom) by using G1s.. but the G83 can't be simulated.

The spiral drill should works with GRBL because this method do not use specific code.

++
David

[Tool-n-Around]

Hello, GRBL do not handle G81, G82 and G83 naturally. If you're using the right post processor, CamBam can simulate the G81 (simple drill) and G82 (simple drill + delay at the bottom) by using G1s.. but the G83 can't be simulated. The spiral drill should works with GRBL because this method do not use specific code.++David

I get the same error with either canned or spiral.

When I look in the grbl machine console the error is "Unsupported GCODE "G81"" (see attached).

My post processor was a proprietary grbl, but I believce that was to support a 4th axis and plasma cutting option. It through a lot or erros and Dave Benson modifed it for me. I believe it had to do with how it interpretted arc. Ever since he made that tweak, it has been solid and produces gcode that works without fail.

I attached the spiral mill file and errors just in case I have something set improperly, but absent that, I must drill holes with the pocket MOP spiral lead in, and depth increments to simulate peck. Would there be a better work around for me or is that best? When holes get small that gets a little difficult becuase of cutter selection, and limited depth, but also I'm not too enthused about plunging even bottom cutting EMs into aluminum that are very near the intended hole diameter and are essentially plunging without other motion.

Best,
Kelly

[lloydsp]

" but also I'm not too enthused about plunging even bottom cutting EMs into aluminum that are very near the intended hole diameter and are essentially plunging without other motion."
----
But, Kelly, you're only cutting 0.062" deep!  A sharp 1/8" endmill will do that with no problems.  That's less than half a tool-diameter.

Lloyd

[dh42]

When I look in the grbl machine console the error is "Unsupported GCODE "G81"" (see attached).

Yep, GRBL do not support G81, the problem is that you do not use the right post pro for GRBL ; the G81 are not "translated" to a series of G1.

example with you drill mop when using a GRBL PP, all G81 are "converted" to G1

with a default PP

Code: [Select]

( Made using CamBam - http://www.cambam.co.uk )
( 351C Valley Pan Opie Bottom R1 CNC Plenum Cover Plate 1/19/2023 9:20:13 PM )
( T3 : 0.125 )
G20 G90 G64 G40
G0 Z0.25
( T3 : 0.125 )
T3 M6
( Drill Points Spiral )
G17
M3 S1000
G0 X8.45 Y-2.547
G98
G81 X8.45 Y-2.547 Z-0.145 R0.25 F5.0
G81 X7.5078 Y-1.033 Z-0.145
G81 X7.0376 Y0.8181 Z-0.145
G81 X7.6 Y2.547 Z-0.145
G81 X5.1459 Z-0.145
G81 X4.115 Y1.4 Z-0.145
G81 Y0.23 Z-0.145
G81 X3.0667 Y2.547 Z-0.145
G81 X0.1897 Z-0.145
G81 X0.5326 Y0.0 Z-0.145
G81 Z-0.145
G81 X-0.0304 Y-2.547 Z-0.145
G81 X2.4176 Z-0.145
G81 X5.4307 Z-0.145
G81 X-2.4784 Z-0.145
G81 X-4.9254 Z-0.145
G81 X-5.9505 Y-1.5401 Z-0.145
G81 X-5.0 Y0.0 Z-0.145
G81 X-3.9192 Z-0.145
G81 X-2.6873 Y2.547 Z-0.145
G81 X-5.5649 Z-0.145
G81 X-6.5188 Y1.532 Z-0.145
G80
G0 Z0.25
M5
M30
and the same with a GRBL PP

Code: [Select]

( Made using CamBam - http://www.cambam.co.uk )
( 351C Valley Pan Opie Bottom R1 CNC Plenum Cover Plate 1/19/2023 9:21:05 PM )
( Post-pro: GRBL )
( T3 : 0.125 )
G20 G90 G40
G0 Z0.25
( Drill Points Spiral )
G17
M3 S1000
G0 X8.45 Y-2.547
G0 X8.45 Y-2.547
G0 Z0.25
G1 Z-0.145 F5.0
G0 Z0.25
G0 X7.5078 Y-1.033
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X7.0376 Y0.8181
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X7.6 Y2.547
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X5.1459
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X4.115 Y1.4
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 Y0.23
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X3.0667 Y2.547
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X0.1897
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X0.5326 Y0.0
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-0.0304 Y-2.547
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X2.4176
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X5.4307
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-2.4784
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-4.9254
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-5.9505 Y-1.5401
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-5.0 Y0.0
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-3.9192
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-2.6873 Y2.547
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-5.5649
G0 Z0.25
G1 Z-0.145
G0 Z0.25
G0 X-6.5188 Y1.532
G0 Z0.25
G1 Z-0.145
G0 Z0.25
M5
M30
What is the PP you have selected ? because nothing selected in the post pro property in the machining folder of your file, I assume it is set as default in Cambam (the one with the green arrow)

My post processor was a proprietary grbl, but I believce that was to support a 4th axis and plasma cutting option. It through a lot or erros and Dave Benson modifed it for me. I believe it had to do with how it interpretted arc. Ever since he made that tweak, it has been solid and produces gcode that works without fail.

Can you share it ? ; certainly the problems with G81 and G82 can be solved.

++
David

[Tool-n-Around]

.......What is the PP you have selected ? because nothing selected in the post pro property in the machining folder of your file, I assume it is set as default in Cambam (the one with the green arrow)

I thought I had been using the PP highlighted in the attached screen shot "Grbl1MillRite" but do see it is set to default. Grbl1MillRite is attached but from the screen shot, it looks like it also does the G1 conversion, correct? How do I identify the default PP and/or change to Grbl1MillRite if that is correct.

Can you share it ? ; certainly the problems with G81 and G82 can be solved.++David

I attached Grbl1MillRite PP

Best,
Kelly

[dh42]

I thought I hade been using the PP highlighted in the attached screen shot "Grbl1MillRite" but do see it is set to default.

On your picture, it is the PP called "default" that is selected as default (it has a small green arrow on the left side)

If you want to select the Grbl1MillRite PP as default, you must right click on it and select "set as default"

I tried the PP you provided, and it works, the G81 and G82 are converted to G1, so I assume that your problem is just that you do not select the right PP as default.

++
David

[Tool-n-Around]

On your picture, it is the PP called "default" that is selected as default (it has a small green arrow on the left side) If you want to select the Grbl1MillRite PP as default, you must right click on it and select "set as default" I tried the PP you provided, and it works, the G81 and G82 are converted to G1, so I assume that your problem is just that you do not select the right PP as default. ++ David

Funny, I tried everything except right click... 

Thanks David, I'll try it again tomorrow with the correct PP and report back.

Best,
Kelly

[dave benson]

Kelly
Some things to keep in mind when drilling holes that have to be accurate.
If the surface is ‘as cast’, then it’s prudent to spot face the holes before spot
drilling them.
A spot drill is has a different angle to a standard drill, for various reasons see pics.
If you find that the hole centers are off a bit then you can turn optimisation off in the mop
and select the holes manually and in such an order that the backlash in the machine is
minimised. (old manual machinist’s trick).
Good luck. Nice looking manifold, are you going to the trouble of port matching it too the
heads.
Just out of interest there's a .nc file from your file from the drilling plugin.
Dave

[Tool-n-Around]

I was able to successfully cut the cover plate for my intake manifold today.

It wasn’t completely without incident. I learned a few things and have a couple new questions. During the course of machining the part, I had a chance to use the drilling MOP. I had the foresight to drill a few test holes and O-ring glands in the waste area of the stock to test feeds and speeds and do some fine tuning to accommodate my machine. I was using a .125” 2 flute spiral carbide end mill. After doing so, the .199” holes were being cut ~.008” under size. That had me scratching my head. I moved on and cut a round O-ring gland with a .25” end mill and it cut correctly. I thought I was going to be coming back here and asking for help on that one and then, I thought to measure the 1/8" end mill……it checked .118”!………somewhere along the line I was sold a 3mm end mill and it should not have happened from the source it came from!

Anyway, I corrected that and got on with it. On the first few test cuts I could tell I was going to need cutting fluid because the cutter was already loading a little with aluminum. The stock was .25” thick ground MIC6 aluminum plate. It’s 7000 series but it is cast. So I manually used a squirt bottle to dispense fluid in front of the cutter as it was cutting. Once some slot depth got established it was easy because it collected the fluid and all I had to do was use the nose of the squirt bottle to drag the chips out of the groove after it was cut. Feedrate was slow so that was easy to keep up with.

The O-ring grooves were .121” wide and .082" deep being cut with a .094 HSS TiNC coated EM. All went well until the first lap of the perimeter O-ring groove. Halfway around the first cut, which was the last operation on the whole part, the end mill tip failed and was obvious from the sound and appearance of cut. The cutter now looked like a point cutting email. Must have gummed up despite my makeshift efforts to lube it. I paused, and the damage was not going to clean up at the present gland size so to save the piece, I decided to increase the O-ring gland size from 3/32” to 1/8” cross section O-ring, and resumed cutting.

It'd probably never make the grade for you guys but it should work fine for me. Pictures attached.

So, the question: After discovering my problem with drilling was the wrong PP, I selected the correct one. In the Tools menu, I have selected “settings saved on exit”. When I went to run the program (using grbl machine plug in), I looked at the PP and it had changed from Grbl1Millrite to Grbl Machine. When I reopened the file just now, it’s back to “default” PP. I didn’t consciously change anything.

How do I save the settings, like the PP, the out file name/extension, number format, etc? I thought that>Tools> “settings saved on exit” would do it but apparently not. Do I need to make a template or other?

Thanks for the help fellas.

Best,
Kelly

[Tool-n-Around]

.....Some things to keep in mind when drilling holes that have to be accurate......

As always, thank you Dave. I always learn something from your replies.

Good luck. Nice looking manifold, are you going to the trouble of port matching it to the heads.

Not the heads. I'm doing this intake for someone else so either he or his engine builder will have to attend to that. I did port match the carb openings to the carbs. The casting lined up fairly well, and it probably wasnt necessary, but since I had it on the mill it was only a few more minutes and some light blending handwork with a burr and cartridge role thereafter.

Best,
Kelly

[dh42]

I have selected “settings saved on exit”. When I went to run the program (using grbl machine plug in), I looked at the PP and it had changed from Grbl1Millrite to Grbl Machine. When I reopened the file just now, it’s back to “default” PP. I didn’t consciously change anything.

maybe it is specific to GRBLMachine plugin, because if I do the same (without the plugin), the default PP selected remain selected on the next session.

I can't test GRBLMachine, (no GRBL machine to connect to)

Seems that the plugin generate its own PP (GRBLMachine.cbpp) when it is run.

If you can't solve the problem, you can try to define the PP in the machining folder, in the Post processor property (in this case it is defined only for the current project)

++
David

[Tool-n-Around]

Thanks David.

When I saw the change to Grbl Machine PP, I thought the same thing, that this is just normal with the plug in. But I have been using the plug in for the past year. I checked to insure that Grbl Machinet handled the Drill MOP conversion correctly and it did, so I used that PP on today's work. What I don't understand is how it changes back to "default", even when I open the same file with Grbl Machine plug in.....strange, but it explains why I mysteriously could not successfully use the Drill MOP.....since somehow the default PP gets activated. I'll experiment a little more but make the PP selection one of my checks before I produce gcode.

I have been working with multiple instances of CB open....maybe that's a clue.

Thanks for all your help.

Best,
Kelly