Cutting cardboard with a knife.

[knight_toolworks]

I have a customer that I cut a fair amount of cardboard on. standard cardboard was ok to cut with a but it was not hard to clean the edges up. but the thick stuff like 1/2" it was really messy. so I came up with a beta cutter to see if it will work. I am working on a better one but thsi one was to try it and see if the blade could follow the cut and if it would work at all.
well it works and I have a video to prove it. it makes drawing things out far harder. a square is just 4 lines with separate tool paths. You have to line the knife up manually and the trick is to know what direction it is going to go. separate toolpaths help control this. I still have to clean up corners and start points with a knife but still it works pretty well. one hard part was finding blades with a hole to I could screw them in place.
http://s154.photobucket.com/albums/s266/knighttoolworks/cnc%20videos/?action=view&current=cuttingwithaknife.flv
http://i154.photobucket.com/albums/s266/knighttoolworks/cnc%20videos/photo1.jpg
http://i154.photobucket.com/albums/s266/knighttoolworks/cnc%20videos/knife.jpg

[john_l]

Hey, you're right. that does work. Pretty neat.

Maybe try to "loop out" the corners in your toolpath so that the blade doesnt need to lift out of the cut until the shape is finished (the outter profile anyway). That is.. toolpath a corner like the exit ramp on a highway... just loop completely around outside the corner and come back in at a 90 degree to the side you left. The blade should just follow along and leave a 90 degree coner.

[myxpykalix]

Steve,
Couldn't you take something like this X-acto knife and use it better? Would it cut better on curves if you had a round blade (like a pizza pie cutter)?

8197

Also regarding toolpathing, this forum upon my fast perusal looked like it was a cutter for flat files and i would bet there would be some type of toolpathing answer where you are not making a toolpath for every line. Do a search for "Ruby" within this forum. I just recall that word as some type of "something" (memory fart..)
http://www.phlatforum.com/

[donclifton]

Will shopbot software allow you to have a tangental cutter on say A axis. I use Mach 3 and it can drive one of the drives as a tanget.

[knight_toolworks]

I tried exacto blades but they had too much flex. I have thought of the loops. it may take more effort to draw them up then it is to cut but time will tell.
I hope to have a new holder today.

[glcochran]

I remember somewhere on the SB website reading about a company who uses a SB to cut out Saddle Pads for horses. Sounds like they have perfected the knife already. Worth some searching!

[scottbot]

Gregory is right.
There was an article in the Spring 2007 newsletter about cutting saddle pads using a rotary cutter on the ShopBot.
http://www.shopbottools.com/newsletters.htm

[knight_toolworks]

I milled out a new knife holder. now the blade is centered. this will make life easier.
I think with the use of tabs I can turn corners. if I put a tab on the corner that just lets the tip of the knife stay in the cardboard it may turn 90's on it's own. I need to test it and see. I need to get the pin to help hold the plade in place.
I made this from 1" bar stock

8198

[donclifton]

Here is a tanget cutter I made to cut fabric. It only cuts cardboard halfway so I'm going to make a knife holder like steve's an see how its done.

http://www.youtube.com/watch?v=FQfIKaq3MZo

[donclifton]

Here is my Cardboad cutter I used a knife like steves.

http://www.youtube.com/watch?v=8nYQaLgvvKI