Wiring a Corner finder and height control

[D-man]

I've just made a similar version edge finder to that of the maker masters project by bill Briggs

my question is, how do we wire these things up to the BOB

[JAZZCNC]

I've just made a similar version edge finder to that of the maker masters project by bill Briggs

my question is, how do we wire these things up to the BOB

Link would be helpful.!! . . . But it's usually just straight to an input so + & gnd just like any limit switch or E-stop.!

[D-man]

Oh I see thanks for that. Would the ground be the tool and the plus the edge finder?

sorry here is the link http://www.themakersguide.com/home/products/triple-edge-finder-2

[Boyan Silyavski]

Most of all depends of your exact BOB. Whats yours? Usually on pin 13 directly if you have pull up resistor there. http://www.autoleveller.co.uk/cnc-probe-guide/

[JAZZCNC]

Oh I see thanks for that. Would the ground be the tool and the plus the edge finder?

Yes but you don't always need the Gnd clip depends if machine/spindle goes to gnd. For safety sake your better using both.

[D-man]

I'm using the uniport

[D-man]

just reading your linksilyavski, is the resistor needed in my application?

[EddyCurrent]

just reading your linksilyavski, is the resistor needed in my application?

No, it says this in the uniport manual;

"Either way you can wire switches between input and ground with no external component needed."

[D-man]

you know, i keep forgetting to read that damn manual! guess i just like testing you guys haha

[JAZZCNC]

Uniport works fine straight from the inputs I used one for 2yrs until it gave up the ghost. My famous Rupert Egg touch probe video was using the uniport.

[D-man]

OK guys i got the touch probe working (ish)

The bit touches the ali plate - stops and backs off
comes down again slower - stops

but rather than reset above it drives the tool down!!

for the purpose of the video - "PLEASE NOTE: No innocent tools were hurt in the making of this video. collet is loose and the tool is wounded volunteer" the thud at the end is the escape key being pressed.

http://youtu.be/6pdbWh9RMbc

[JAZZCNC]

Presume your using gerry's screen set.?

Have you set the clearence plane.? and is the number positive not negative.?

With all the issues you have been having with changing axis directions etc could you possible have the Z axis going in wrong direction.? IE down = positive Z axis are nearly always negative moves down with positive up.!

Test by zeroing dro clear of any obstructions and typing G1 Z-5 F100 in the MDI box. This will move nice an slow 5mm down. If goes up your set wrong.!

[D-man]

Cheers JAZZ,

yeah im using said screenset.

I done G1 Z-5 F100 and the axis goes down 5mm

Clearance is +5.000

still driving intop the plate

screen shot - http://prntscr.com/51wias

[D-man]

went into the simple zero file does this make sense?

Else ' Off = Metric Measure MM

FirstProbeDist = 150.0 ' Probe down 150mm
FirstRetractDist = 1.0 ' Then retract 1mm
SecProbeDist = 6.0 ' Then probe down 6mm
FirstProbeFeed = 250.0 ' First probe feed @ 250 mm/min
SecondProbeFeed = 25.0 ' Second probe feed @ 25 mm/min
ClearAllow = 2.0 ' Max Allowable Clearance = Z Machine Zero - 2mm



i cant read that lol

[D-man]

now sorted... doesnt make sense to me however. set the material clearance to 20mm then an offset of 4.3 and its spot on.

[Ger21]

went into the simple zero file does this make sense?

Else ' Off = Metric Measure MM

FirstProbeDist = 150.0 ' Probe down 150mm
FirstRetractDist = 1.0 ' Then retract 1mm
SecProbeDist = 6.0 ' Then probe down 6mm
FirstProbeFeed = 250.0 ' First probe feed @ 250 mm/min
SecondProbeFeed = 25.0 ' Second probe feed @ 25 mm/min
ClearAllow = 2.0 ' Max Allowable Clearance = Z Machine Zero - 2mm



i cant read that lol


Those are hard coded default values, and have nothing to do with the issue.

Really, there should be no way that it can plunge down after probing.

I'd need to know what the message on the screen said after it plunged down.

PS. Your collet nut is too loose. :thumbdown:

[D-man]

Sorry Gerry, did I spoil it for you by leaving it loose lol sorry pal.

Wife's just cooking me some steak and peppercorn sauce, I can't go anywhere until I've destroyed it, so will pop to the factory afterwards and let you know.

[D-man]

I will reset to default values and do another video for you Gerry with screen included

[D-man]

OK after setting back to defaults (when the bit plunges) it says that the "Z axis is now Zeroed"

video uploading

[D-man]

Ok Setting back to defaults with 3mm clearance. still goes down.

http://youtu.be/dlAoPufx4ck

Second attempt, with clearance set to 20mm Goes up! but plunges too far when set to top of work piece.

https://www.youtube.com/watch?v=Jo4E8USpKDs&list=UUj8iYhhCj31t3QMlcAUlD8w&index=2

Third attempt, works great with a 5.3 offset and same settings as above. go to zero and it just kisses the work piece

https://www.youtube.com/watch?v=wg7JY5X8HPM&list=UUj8iYhhCj31t3QMlcAUlD8w&index=1

i do have safe Z set in mach would that affect it (Back at home now)

[Ger21]

Sorry, I stepped out for a bit.


I will reset to default values and do another video for you Gerry with screen included

What had you changed? What you posted before were the defaults.

What is your Safe Z set to? Is it set to Machine Coordinates?


Third attempt, works great with a 5.3 offset and same settings as above. go to zero and it just kisses the work piece

Not great, as Z zero should be 5.3mm above the workpiece.

Leave the Material Offset unchecked until you get it to zero reliably without plunging. This just adds more complexity to the equation.



Second attempt, with clearance set to 20mm Goes up! but plunges too far when set to top of work piece.

Can you try this again, and tell me what the DRO says when it finishes? If your plate is 16mm, then it should finish 4mm above the plate, and the Z DRO should read +20.000

After probing, the macro sens a single G0 Z move to the clearance plane, which should be UP.

[Ger21]

After reading my manual and watching your videos a few more times, I've determined that the issue is operator error on your part. :glee:

Your plate thickness is 16mm. The bottom of the plate is Z = 0. Your clearance plane is Z=3, resulting in the tool plunging 13mm into the plate.

I'm still a bit confused about the time you had a material offset of 5.3mm, as Z zero should have been 5.3mm above the table???

[D-man]

Yeah its defiantly my fault. I just don't understand why after the second touch it goes down rather than up to clear.

You ain't even got time to quickly whip the plate from under it so it don't hit the plate.

[Ger21]

Yeah its defiantly my fault. I just don't understand why after the second touch it goes down rather than up to clear.


As I said:

Your plate thickness is 16mm. The bottom of the plate is Z = 0. Your clearance plane is Z=3, resulting in the tool plunging 13mm into the plate.

[D-man]

But shouldn't it rise 3 mm. To get the plate out and then drop 19 mm to Z 0 when goto zero is pressed or am I grasping this thing all wrong?

(16+3=19. Go to zero -19 in the positive direction)

And then for an example if an offset of say 5mm is set, then it would offset from Z zero 5mm

Is it possible that the plate is too thick for the settings/script? Reason i ask is when a clearance of 20mm is entered it then goes up. But then plunges too far

[D-man]

Right, this is embarrassing!

for starters my plate thickness is not 16mm! i cut a 5mm pocket where it sits on the corner of the workpiece!! so in actual fact it is 11mm!!

i shall let you know if anything changes!

[D-man]

nope! still drives into the plate after the second touch

[firetrappe]

Leave the 'Material offset' unchecked for now. Enter your 'plate thickness' as 11mm and enter your 'clearance plane' as 20mm. This will make the tool raise to 20mm above your workpiece material after probing (9mm above your plate).

[D-man]

Strangly enough that worked! however, when i press "go to zero" the tool plunges into the material around 0.2mm shall i use the "offset" to counter act that?

Z axis steps etc has been set up and is spot on.

[firetrappe]

Glad you're getting somewhere now.

The tool is probably plunging into the material because your plate thickness isn't exactly 11mm thick. Measure the thickness as accurately as you can and change the plate thickness value. For example, my plate is just a piece of copper clad circuit board and it is 1.56mm thick, that is the value I use.

[Ger21]

Thanks firetrappe fpr helping to sort this out. I think we've got all our answers now.


But shouldn't it rise 3 mm. To get the plate out and then drop 19 mm to Z 0 when goto zero is pressed or am I grasping this thing all wrong?

(16+3=19. Go to zero -19 in the positive direction)


No, the Clearance Plane is not an offset amount. It's the Z level where all rapids are performed at, in Work Coordinates. The manual explains in a little more detail on what it should be set to (Page 11). It MUST be a larger value than the plate thickness. If your fixed plate is higher than your movable plate, the Clearance plane needs to be higher than that plate as well.



for starters my plate thickness is not 16mm! i cut a 5mm pocket where it sits on the corner of the workpiece!! so in actual fact it is 11mm!!

And now we know why the Material Offset was not set correctly.



Strangely enough that worked!

Not strange at all had you followed the instructions in the manual. :encouragement:


however, when i press "go to zero" the tool plunges into the material around 0.2mm

Because your plate is probably 10.8mm thick. Do you have a caliper or micrometer you can measure it with? Also, with such a large plate, it's important that it's perfectly flat, and is lying on a perfectly flat surface.


shall i use the "offset" to counter act that?

NO!!! If your plate thickness value is set correctly, your Z zero will be set correctly. Trust me, this works for thousands of other users.

Read the manual for an explanation of what the Material Offset can be used for.

[D-man]

Thanks Gerry. I DID read the manual, however i think ive just been a little confused as to what some things mean...

For example:

I thought that the "clearance" was that above the PLATE not from the bottom of the plate and then some.

Plus the fact i may have been thinking too much about my steaks lastnight!!

I appreciate it guys thank you very much! even tho its made me look as thick as pig s*** :joker:

[Ger21]

I thought that................

Thinking always gets people in trouble. :beer:

[Clive S]

Thinking always gets people in trouble. :beer:

I have that trouble as well. Glad it is now sorted for you. ..Clive

[D-man]

yeah cheers guys, feel like a pro now when im setting up haha

[firetrappe]

Glad to see you've got it working and understand the parameters now.

Seeing as you're new to probing, here are a few tips that might help you..

Assuming that your setting your jobs up with z0 being the top of your workpiece :

When cutting pockets, slots or engraving/v-carving do as you're doing now - put the touchplate on top of the workpiece and zero to top. This means your cuts will be the exact depth that you've programmed.

When cutting profiles (full depth of your material) then put your touchplate on your spoilboard (probably upside-down in your case as you have a lip on the bottom) and zero to the spoilboard. THEN, click in the Z axis DRO and SUBTRACT the thickness of your workpiece material from whatever the DRO is showing. ie. if the DRO shows 30.000mm and your material thickness is 10mm change the Z DRO to value to 20.000mm.

The reason for doing this is that your workpiece may not be exactly the thickness you think it is. For example, I recently bought some 18mm thick plywood from B&Q. It turned out that it actually measured 15.5mm thick. I'd programmed my toolpaths based on the material being 18mm. If i'd probed to the top of the material then I would have ended up cutting 2.5mm into my spoilboard - and the 2mm tabs i'd programmed to prevent the part breaking free wouldn't have worked. Probing to the spoilboard meant that my spoilboard wasn't damaged and the tabs worked. It also means that if your material is slightly thicker then you'll still cut all the way through rather than leaving an onion-skin.

I use a similar method for surfacing my spoilboard too. I have a toolpath created to surface my spoilboard which has a cutting depth of zero. To use the file, i'll probe to my spoilboard as above, then click the Z-DRO and ADD the amount that I wish to take off the spoilboard. ie, if my Z DRO is showing 30.000mm then i'll change it to 30.200mm. This will take 0.2mm off the spoilboard and means I can have one 'surfacing' gcode file which can be changed on-the-fly to remove as much or little material as I want.

I hope I haven't confused you even more, but these procedures work for me and might help someone else reading this thread.

Si.

[Ger21]

When cutting profiles (full depth of your material) then put your touchplate on your spoilboard (probably upside-down in your case as you have a lip on the bottom) and zero to the spoilboard. THEN, click in the Z axis DRO and SUBTRACT the thickness of your workpiece material from whatever the DRO is showing. ie. if the DRO shows 30.000mm and your material thickness is 10mm change the Z DRO to value to 20.000mm.

The reason for doing this is that your workpiece may not be exactly the thickness you think it is. For example, I recently bought some 18mm thick plywood from B&Q. It turned out that it actually measured 15.5mm thick. I'd programmed my toolpaths based on the material being 18mm. If i'd probed to the top of the material then I would have ended up cutting 2.5mm into my spoilboard - and the 2mm tabs i'd programmed to prevent the part breaking free wouldn't have worked. Probing to the spoilboard meant that my spoilboard wasn't damaged and the tabs worked. It also means that if your material is slightly thicker then you'll still cut all the way through rather than leaving an onion-skin.

THIS is what the Material Offset was designed to be used for. :triumphant:

Just set the Material Offset to 18, and zero to the spoilboard, and your Z zero will be set 18mm above the spoilboard. No need to be changing DRO values. The screenset can handle this automatically.




I use a similar method for surfacing my spoilboard too. I have a toolpath created to surface my spoilboard which has a cutting depth of zero. To use the file, i'll probe to my spoilboard as above, then click the Z-DRO and ADD the amount that I wish to take off the spoilboard. ie, if my Z DRO is showing 30.000mm then i'll change it to 30.200mm. This will take 0.2mm off the spoilboard and means I can have one 'surfacing' gcode file which can be changed on-the-fly to remove as much or little material as I want.

You can use the Material Offset with a negative value to do this.

[firetrappe]

Gerry, thanks for the clarification of the Material Offset parameter. I did use that originally but found that I sometimes forgot to change it as I always have the 'Run' tab showing. I find it easier to remember to change the DRO but that's just my personal preference.

Si.

[Ger21]

I almost added the statement that the only problem with the Material Offset, is forgetting that it's on or off. :friendly_wink: