Nesting/Cutting Rectangle Parts

[tstuds]

Hi,

New user here, we are soon to have a new router with a bed size of 1250mm x1000mm and will mainly be used in a production environment.

Most of our parts will be basic square or rectangle parts so in order to keep runtimes as short as possible I want to use what I would call "common line cutting" so nest my parts at say 6mm apart and use a 6mm cutter then cut the entire sheet as a grid and not cut around every part individually.

I assume the only way to do this would be to create a new vector down the centre of the space between my parts and ignore the part outer profile?

Any tips on cutting lots of square parts for production would be gratefully received, I know we might not get the best edge finish doing it this way but for what we need it should be ok.

Cheers

[jimwill2]

Why not just layout individual lines that will create your parts? If you aren't using a vacuum bed you can leave a little "onion skin" to hold your sheet together.

[tomgardiner]

There is no automatic way to layout a common cut line in V-Carve. For files that will be used repeatedly you can spend the time to layout your parts with the same width or height in a grid. You can drag a rectangle by a corner and snap to its neighbor. Pressing the M key will bring up the move function and a relative move will space the parts by the bit dimension.
You can optimize the cuts by node editing (N on the keyboard) changing the start point will reduce the non cut travel. In the toolpath settings check the box always use start points. If the advanced settings option is checked you can choose from the Order tab - vector selection order.
If other operations are being done to the parts be careful not to disturb the other elements associated with those parts as you move them around. You can group a selection quickly by keying G ungroup U.
That is a start

[tstuds]

Why not just layout individual lines that will create your parts? If you aren't using a vacuum bed you can leave a little "onion skin" to hold your sheet together.

Thanks, thats pretty much what I thought.

[tstuds]

There is no automatic way to layout a common cut line in V-Carve. For files that will be used repeatedly you can spend the time to layout your parts with the same width or height in a grid. You can drag a rectangle by a corner and snap to its neighbor. Pressing the M key will bring up the move function and a relative move will space the parts by the bit dimension.
You can optimize the cuts by node editing (N on the keyboard) changing the start point will reduce the non cut travel. In the toolpath settings check the box always use start points. If the advanced settings option is checked you can choose from the Order tab - vector selection order.
If other operations are being done to the parts be careful not to disturb the other elements associated with those parts as you move them around. You can group a selection quickly by keying G ungroup U.
That is a start

Cheers, its good to know I was on the right track, im sure ill have some more questions once we are up and running.

[martin54]

Nothing to do with your cutting question, more about your choice of machine. If you are operating in a production enviroment would you not be better off with a bigger machine? The size you have mentioned to me would produce a lot of waste material unless you only intend to use it for one specific job. I don't do prouction work but have done jobs where I wish the machine I had would take a full sheet so I could make better use of my material when cutting multiples from sheet materials.

[tstuds]

Nothing to do with your cutting question, more about your choice of machine. If you are operating in a production enviroment would you not be better off with a bigger machine? The size you have mentioned to me would produce a lot of waste material unless you only intend to use it for one specific job. I don't do prouction work but have done jobs where I wish the machine I had would take a full sheet so I could make better use of my material when cutting multiples from sheet materials.

Yeh I agree with what you are saying, but we are now limited on space and im told the material we will be using (Vermiculite board) is a little delicate so sheet sizes are kept small.

[Adrian]

You might struggle with the corners with that type of board with common line cutting. It was a few years ago now but I had a contract to cut lots for a wood stove manufacturer and it was incredibly easy to break the corners while cutting if the bit was putting pressure on the finished part rather than the waste. It's easier to play around with conventional/climb cutting when each part has its "own" vector.

[tstuds]

You might struggle with the corners with that type of board with common line cutting. It was a few years ago now but I had a contract to cut lots for a wood stove manufacturer and it was incredibly easy to break the corners while cutting if the bit was putting pressure on the finished part rather than the waste. It's easier to play around with conventional/climb cutting when each part has its "own" vector.

Hi Adrian, we are a Stove Manufacturer looking at bringing the job of cutting fire bricks in house.

Don't suppose you could give me any advice on types of tools used and a starting point for speeds and feeds? I know there are many factors that will affect this, the main one I imagine being the vacuum table and keeping the sheet and parts in position whilst cutting. I have lots of experience with Laser/Plasma cutting, folding steel and programming setting and operating a 15 axis swiss mill/turn lathe so im not new to CNC just never played with wood or vermiculite or VCarve.

[Adrian]

I started off using a 6mm two flute spiral down cutter running at 11000rpm with a feed rate of 400ipm with the pass depth set to be 1 pass but with a spiral ramp set. I didn't experiment that much with the feed rates as the material didn't give the sort of feedback you would get from a normal wood material so it was hard to dial it in exactly.

I didn't use a vacuum hold down with these as I generally find I don't need it with materials over 10mm or so thickness and a reasonable amount of weight. You could probably dispense with the spiral ramp with a vacuum hold down.

[tstuds]

I started off using a 6mm two flute spiral down cutter running at 11000rpm with a feed rate of 400ipm with the pass depth set to be 1 pass but with a spiral ramp set. I didn't experiment that much with the feed rates as the material didn't give the sort of feedback you would get from a normal wood material so it was hard to dial it in exactly.

I didn't use a vacuum hold down with these as I generally find I don't need it with materials over 10mm or so thickness and a reasonable amount of weight. You could probably dispense with the spiral ramp with a vacuum hold down.

Ok thanks, every bit of knowledge helps. Our maximum thickness will be 50mm, we have found a 3 flute end mill with 50mm of flute length and plan to try and cut at max depth but im concerned about chip/dust evacuation and heat.