Donek D3 Dragknife - Zeroing Issues

[benway]

Hey Gang,

Did a cursory search and was surprised not to see any threads about dragknives. Does anyone have experience with this particular brand with their axiom machine? Pretty sure my file is setup correctly with the dragknife widget in VCarve, offset, and all numbers entered correctly. I also know to align it to the direction of travel it will take from it’s start node. No trouble there
My problem is that I can’t get the blade to zero properly.
I have an original 2”x4” (Ar8 or 9?) bed with the initial controller axiom sold. Can’t use the zeroing puck because the ulility blade isn’t recognized (proben by the large gash it now boasts).
Tried manual zero but havent done it ever so a primer might be good there as well. Thanks in advance.

[gerry]

I've been playing with my D2 knife. I'm using a vacuum board, freshly skimmed and 0.05 paper stock. So far, I've zeroed on my paper, then had to drop the Z by 0.1mm to get a good cut. I think it is bearing play in the knife when pressure is applied. I started test cuts zeroed on the paper, then dropping it each test pass to test cut. So far, a LOT of fiddling to get a decent cut. I have found that I'll have to come up with some kind of 'creaser' to mark folds of box. Crease first, then cut. Manually drawing creases doesn't work very well.

[benway]

Hey Gerry,
Thanks for the info/reply. I think the trouble I'm having is in manually zeroing the knife.
The stock manual isn't the most helpful, haven't found a comparable video, and I've had trouble getting it to Zero at the correct xyz coordinates, which is why it keeps trying to destroy itself every time.
In terms of what you're telling your controller, how do you manually zero when you're using your dragknife?

Here's what I've done in terms of my most likely faulty process:
1. Did the Home all function via the, "HOME" button. which starts from my front-left corner.
2. Stepped the blade down to the material surface (which is .01) thick
3. Pressed "ORIGIN OK"
4. Nearly destroy $250 dragknife 2 times

*Guessing the use of the "XY->0" and "Z->0" buttoms could be the answer?

I know this is newb stuff, (I swear I've had my machine for at least 4 years) but something just isn't right.
I rechecked the .mmg and the settings are as follows:

Dragknife Gadget: -Cut Depth: .02 (it's sailcloth) -Swivel depth: .015 (I have rounded corners so not an issue). -Blade Offset:.065 (D3 cutter) -Tolerance Angle: 20 (the default).
"Dummy" Tool: -Diameter: .02 -Pass Depth: .01 -Stepover: .008 (the machine set this when I changed the Diameter to .02) -Spindle Speed: 0 -Feed Rate 60inch per min. -Plunge Rate: 10

I know that once I get in the ballpark I'll have some honing/tuning based on my particular application, but I'm still having trouble finding the door!

PS: An empty ballpoint pen might make a good "creaser" or scoring device in the absence of a scoring wheel or the desire to do it manually. You'd just need one with a stiff pen barrel that'll fit whatever collet you have.
Cricut (I know, the mere utterance is probably considered sacrilege in cnc land) makes a scoring tool that's essentially a ball-tip mounted in a similar manner so that it can roll freely under pressure. it makes a slick, clean score and I'm sure you could modify it to suit your purpose.

[gerry]

I have the B18 controller.

1. HOME X, Y, Z on startup.
2. Position knife tip to where I want Job XY=0. Hit 'XY->0' key. X & Y are now each 0. I drop Z until knife just pierces board. Set Z=0 with 'ZC->0' key.
3. Raise Z to safe height.
4. Start job.
5. If paper not cut through, I drop Z to -0.1 then hit 'ZC->0' key. Goto 3. & repeat until satisfactory.

The Cricut creaser sounds good. I'll look for it. My oldest boy has a Fadal mill in his garage, so I have an edge on getting fixtures made.

[benway]

Excellent! Thanks. All makes sense. Can't believe how dependent I was on the puck for zero. I have the A11 controller, but know which buttons to press.
Will post with results.

Lucky having access to a mill like that.
I would totally buy said creaser and some kind of rotary cutter over the drag knife (I'm going to mainly be cutting fabric) if I could find a decent one for sale.
Here's a link so you can see it quickly: Cricut Debossing Tip

[johnb]

Not trying to go off-topic here (since y'all seem to be about cutting with a drag knife), but do any of you have experience with any of the diamond drag knives that are "out there"?

BTW...benway...that is the most disturbing avatar I've ever run across 😂

[gerry]

Jan 23, 2020 9:05:47 GMT -5 johnb said:

Not trying to go off-topic here (since y'all seem to be about cutting with a drag knife), but do any of you have experience with any of the diamond drag knives that are "out there"?

Diamond drag knife??? There is no such animal. There are drag knives, diamond drag bits.....

[johnb]

Jan 23, 2020 13:30:31 GMT -5 gerry said:

Jan 23, 2020 9:05:47 GMT -5 johnb said:

Not trying to go off-topic here (since y'all seem to be about cutting with a drag knife), but do any of you have experience with any of the diamond drag knives that are "out there"?

Diamond drag knife??? There is no such animal. There are drag knives, diamond drag bits.....

Yeah...my bad "diamond drag bit" or "diamond drag engraver".  While on that topic, I wonder if one of those could serve the "creasing" function which you discussed? They are spring loaded and the pressure applied is a factor of the "cutting depth" that you set. With sailcloth, you'd want to "smash" or crimp the fibers without breaking any of them...methinks?

[gerry]

Diamond drag bits work fine. I've used them for engraving acrylic and some metals. They're cheap enough to try. I think I got both of mine on ebay.

[colofan]

To add to the discussion I have the donek as well however I also have
"Sign Vinyl Drag Knife Bit for CNC Machines Brand: WidgetWorks Unlimited LLC."

Works great for thin materials and a really small klnife that is spring loaded which makes cutting the criscut material pretty easy. Not cheap but nothing that has CNC in the name is