cutting a single pass?

This forum is for general discussion regarding VCarve Pro

cutting a single pass?

Postby cbarens10 » Sat Jan 05, 2019 10:15 pm

Hi guys - I have a dilemma/question, I am running a Vcarve file on a Shopbot CNC and it is not cutting all the way through my material. Is it possible to run a single pass deeper when its done? I have no idea how to program that and it will be a huge PIA to cut these parts out with a jigsaw.
cbarens10
 
Posts: 8
Joined: Mon Dec 11, 2017 12:39 am
Model of CNC Machine: Shopbot 4×8 CNC Router

Re: cutting a single pass?

Postby highpockets » Sat Jan 05, 2019 10:36 pm

In the toolpath make sure the Cut Depth is equal or more than your material thickness.
John
Maker of Chips
User avatar
highpockets
Vectric Wizard
 
Posts: 2417
Joined: Tue Jan 06, 2015 4:04 pm
Model of CNC Machine: PDJ Pilot Pro

Re: cutting a single pass?

Postby SteveNelson46 » Sat Jan 05, 2019 10:40 pm

Are you setting your Z0 to the spoil board or to the top of your work piece.
Steve
User avatar
SteveNelson46
Vectric Wizard
 
Posts: 545
Joined: Wed Jan 04, 2012 2:43 pm
Location: Tucson, Az.
Model of CNC Machine: Camaster Stinger with Recoil Lathe

Re: cutting a single pass?

Postby martin54 » Sat Jan 05, 2019 11:09 pm

If you are profile cutting then yes you can, run another toolpath with the start depth set at the depth you finished cutting & the cut depth to what ever material thickness is left to cut through :lol: :lol:

so if your material thickness was say 21mm & you had already cut to 20mm bcause you thought that was what the material was then you would make a toolpath with a start depth of 20mm & a cut depth of 1mm or slightly more than 1mm if you wanted to be sure :lol: :lol: :lol:
User avatar
martin54
Vectric Wizard
 
Posts: 4626
Joined: Fri Nov 09, 2012 2:12 pm
Location: Crossgates, Scotland
Model of CNC Machine: Gerber System 48 (modified)

Re: cutting a single pass?

Postby Leo » Sat Jan 05, 2019 11:19 pm

You can CERTAINLY run a final pass at full depth after you run your multiple passes. Simply create another tool path on the same vector but with a full depth pass rather than multiple pass depths. Post both toolpaths as one post and it will happen for you.
Imagine the Possibilities of a Creative mind

www.leosworkshop.com
User avatar
Leo
Vectric Wizard
 
Posts: 2950
Joined: Sat Jul 14, 2007 3:02 am
Location: East Freetown, Ma.
Model of CNC Machine: 1300 x 1300 x 254

Re: cutting a single pass?

Postby cbarens10 » Mon Jan 07, 2019 12:26 pm

thanks everyone I got my answer, I'm still not sure why it didn't cut through. I zeroed correctly, material was flush, and the thickness was .75" and I set the cut depth to .77". This has been a frustration for me, as I don't want to cut into the spoilboard. The vacuum at the shop is missing the downward flashing that keeps it close to the material, and I think because there was a lot of chips on the plywood that may have been part of it.

What extra cut depth do you use? Is .0625" too much?
What would you all recommend as the best bit for cutting .75" hard plywood? I have only used an EM .25" double flute, should I try a compression bit? I like Onsrud.
cbarens10
 
Posts: 8
Joined: Mon Dec 11, 2017 12:39 am
Model of CNC Machine: Shopbot 4×8 CNC Router

Re: cutting a single pass?

Postby martin54 » Mon Jan 07, 2019 12:53 pm

You said it hasn't cut through all the way, is that the whole piece or has it cut through in some parts but not others? When was the last time you checked your spoilboard, your machine spindle was trammed & the calibration of the machine?
If they are all good then the only other things I can think of to to check are your z zeroing & your collets, have you checked the machine is zeroing to exactly the same spot after the cut? If not then the bit could be slipping in the collet.
I like straight flute bits for plywood, they seem to give me a better edge finish than spirals but I am not an expert, I don't use commpression bits because of the cost, the amount of work I would use them for just doesn't justify the expence but if I were doing more work where they would be of benefit then I would certainly look at buying them :lol: :lol:
User avatar
martin54
Vectric Wizard
 
Posts: 4626
Joined: Fri Nov 09, 2012 2:12 pm
Location: Crossgates, Scotland
Model of CNC Machine: Gerber System 48 (modified)

Re: cutting a single pass?

Postby tomgardiner » Mon Jan 07, 2019 2:42 pm

Depending upon the cutter, I will set my depth to z+. 002". For down shear bits I will go deeper but never more than .010". I'm too cheap - at .010" per spoilboard resurfacing I would be replacing my board too often.
My go to bit is a 3/8" compression bit for cabinet parts mostly because I get dozens of sheets out of a single sharpening but I am with Martin, a straight flute often gives me a cleaner cut when sharp at the expense of speed.
tomgardiner
Vectric Wizard
 
Posts: 362
Joined: Thu Oct 02, 2014 1:49 pm
Model of CNC Machine: FMT Patriot 4 x8

Re: cutting a single pass?

Postby SteveNelson46 » Mon Jan 07, 2019 2:51 pm

Although most 3/4" plywood is marketed as .75 inches, it rarely is. Use a set of accurate calipers to be sure.
Steve
User avatar
SteveNelson46
Vectric Wizard
 
Posts: 545
Joined: Wed Jan 04, 2012 2:43 pm
Location: Tucson, Az.
Model of CNC Machine: Camaster Stinger with Recoil Lathe

Re: cutting a single pass?

Postby Fleming » Mon Jan 07, 2019 3:38 pm

To solve the problem of cutting the spoilboard I set my material on top of those rubber spacers used to separate ceramic tiles. They are uniform thickness (about 1/8"), doesn't matter if your cutter hits them as they are soft rubber, are sold by the bag, and are inexpensive!
Cobblewood Carver
Fleming
Vectric Wizard
 
Posts: 325
Joined: Tue Oct 28, 2008 3:41 pm

Re: cutting a single pass?

Postby Adrian » Mon Jan 07, 2019 3:57 pm

The whole idea of a spoilboard is that it gets chewed up over time and is resurfaced when needed though so cutting into it isn't really a problem as such.
User avatar
Adrian
Vectric Archimage
 
Posts: 9592
Joined: Thu Nov 23, 2006 2:19 pm
Location: Surrey, UK
Model of CNC Machine: ShopBot PRS Alpha 96x48

Re: cutting a single pass?

Postby SteveNelson46 » Mon Jan 07, 2019 4:00 pm

I agree with Adrian. IMHO, a spoilboard is just as the name implies. It's sacrificial.
Steve
User avatar
SteveNelson46
Vectric Wizard
 
Posts: 545
Joined: Wed Jan 04, 2012 2:43 pm
Location: Tucson, Az.
Model of CNC Machine: Camaster Stinger with Recoil Lathe

Re: cutting a single pass?

Postby martin54 » Mon Jan 07, 2019 6:04 pm

Not that I would want to disagree with Adrian :lol: :lol: :lol: :lol: But I don't like cutting into the spoilboard & avoid it by setting my Z0 to the spoilboard when I set up a project in the software as one method or my other method when working off the top of the material is to set my cutter to the spoilboard BUT enter the material thickness as a negative number for my Z height rather than hitting the Z zero button in the control software :lol: :lol: :lol:

Quick edit, I would only use method 2 if I were cutting parts out, for anything else I would set my z zero to the material surface as normal :lol: :lol:
User avatar
martin54
Vectric Wizard
 
Posts: 4626
Joined: Fri Nov 09, 2012 2:12 pm
Location: Crossgates, Scotland
Model of CNC Machine: Gerber System 48 (modified)

Re: cutting a single pass?

Postby Leo » Mon Jan 07, 2019 6:30 pm

I will cut into sacrificial spacers placed under my workpiece.

I cut pressed hardboard into strips and burn than when they are no longer any good.

One 4x8 sheet of pressed hardboard (masonite) goes a long way when cut into 3" wide by 48" long strips.

I don't really have a spoil board on my machine.
Imagine the Possibilities of a Creative mind

www.leosworkshop.com
User avatar
Leo
Vectric Wizard
 
Posts: 2950
Joined: Sat Jul 14, 2007 3:02 am
Location: East Freetown, Ma.
Model of CNC Machine: 1300 x 1300 x 254

Re: cutting a single pass?

Postby woody53 » Tue Jan 08, 2019 2:30 am

I am sorry to say I really don't understand all the fuss about a spoil board. That's what it is . I always check my material with a caliper and set my z height to the material. I've had my machine for 5 years and surface spoil board when needed, second one in 5 years. I am sure not anywhere as good as most on here, but simple should be simple. Check twice , cut once. Have been building cabinets for 45 years, and still do it only , the cnc makes things a lot easier.


Dave
woody53
Vectric Wizard
 
Posts: 303
Joined: Sat Jun 11, 2011 3:27 pm
Location: Jefferson City, Mo.
Model of CNC Machine: Probotix Meteor 25 x 50


Return to VCarve - General

Who is online

Users browsing this forum: tomgardiner and 30 guests