Large Format Fabric Cutter

Pyronaught
Posts: 9
Joined: Wed Sep 25, 2013 5:33 pm

Large Format Fabric Cutter

Post by Pyronaught » Wed Sep 25, 2013 7:04 pm

I just got done building this 16foot x 5.5 foot fabric cutting machine which uses 43 feet of makerslide. I looked at a lot of options for how to build a machine this large without breaking the bank and makerslide was the optimal solution. Not only is this the most economical way of building a large format fabric cutter, it is also one of the most light-weight and expandable designs. To make the table longer, you just add more table segments with rail. Since the X axis is chain drive, you can splice on more chain to increase the length.

Because of the light weight I can easily run rapids at 1300 IPM or more. Rigidity is not as much of an issue here since there is no heavy spindle with side forces acting on it the way there is with a router. The levelness of the table does not matter much either, since the tool head is pneumatically actuated and will hold the tool to the table regardless of any dips or peaks in the table surface (as long as they are within the range of the cylinder stroke).

In the videos below I am using a hot-knife cutter which I built from an 80W soldering iron. This cutter has tangential cutting capability, so there is a blade rotation motor that keeps the blade tangent to the cutting line as it goes. For drag knife you just wouldn't use this motor, but for hot knife and wheel cutters you would need it. Currently all I have made is the hot knife, since that is the main thing I need, but other knife types could be made and inserted into the tool shaft in place of the hot knife.

The entire table surface is a vacuum table powered by two 5HP Rigid shop vacs under the table. I will mainly be using this for cutting coated ripstop nylon for the purpose of building hot air balloons, which air can not pass through so the vacuum table holds it down quite well. The loud noise you hear in the videos is from the shop vac running while cutting.

Total build time was about three months and material costs were about $3K, which also includes a small air compressor to run the pneumatics. A commercial machine this size would run you about $30K, so that is quite a bit of savings!

Here’s some video of the first tests:


http://www.youtube.com/watch?v=FFzpVG-TPCQ

http://www.youtube.com/watch?v=UEWpTvf-1Tk
Attachments
build_table_11.jpg
Vacuum system
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build_gantry_1.jpg
Working on the gantry
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build_table_7.jpg
Building the table frame
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Pyronaught
Posts: 9
Joined: Wed Sep 25, 2013 5:33 pm

Re: Large Format Fabric Cutter

Post by Pyronaught » Wed Sep 25, 2013 7:08 pm

More pictures, since there is a 3 picture limit on attachments...
Attachments
build_controller2_3.jpg
old PC case converted into a controller chassis
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cnc_fabric_cutter_10.jpg
Support shelf to prevent sagging when running long lengths of drag chain
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build_gantry_9.jpg
Pneumatic valve manifold
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Pyronaught
Posts: 9
Joined: Wed Sep 25, 2013 5:33 pm

Re: Large Format Fabric Cutter

Post by Pyronaught » Wed Sep 25, 2013 7:16 pm

More pictures...
Attachments
cnc_fabric_cutter_11.jpg
Tool head w/pen and hot knife
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cnc_fabric_cutter_4.jpg
Valve manifold for controlling blade/pen pressure
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build_controller2_1.jpg
Completed controller (e-stop is remotely located on the control console)
build_controller2_1.jpg (206.32 KiB) Viewed 8638 times

Gadgetman!
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Re: Large Format Fabric Cutter

Post by Gadgetman! » Wed Sep 25, 2013 8:41 pm

Nice!

In the second video, you have the cutting time down to 2 minutes and something...
How long would it have taken to do it manually?

How long would it normally take to lay out and cut the fabric for an entire balloon manually?
And how long would it take with this cutter?

It's probably improving the quality, and reducing the amount of scrapped pieces caused by faulty cuts, too?
Weird guy...
Shapeoko 2014F: 1000mm X/Y, 300W Quiet Cut spindle, Arduino Uno/G-shield and GRBL 0.9i
15x30 drag chains, custom spindle mount, 9mm belts, 8mm endplates, 6mm motor plates.

Pyronaught
Posts: 9
Joined: Wed Sep 25, 2013 5:33 pm

Re: Large Format Fabric Cutter

Post by Pyronaught » Wed Sep 25, 2013 9:29 pm

Gadgetman! wrote:Nice!

In the second video, you have the cutting time down to 2 minutes and something...
How long would it have taken to do it manually?

How long would it normally take to lay out and cut the fabric for an entire balloon manually?
And how long would it take with this cutter?

It's probably improving the quality, and reducing the amount of scrapped pieces caused by faulty cuts, too?

Manually cutting out the roughly 300 panels it takes to make a typical balloon can take weeks. First you have to plot out a template on paper that you use for a guide, so just that stage alone is a major pain and introduces the potential for error. Then you have to secure each sheet of fabric to the table using staples, weights or something to keep it from moving prior to cutting it. The actual cutting of the panel might only take twice as long, since you can move the cutter at about the same speed as the machine (feed rate is limited with a hot knife), so the extra time is from having to walk back and forth from one side of the table to the other since you can not reach all the way across from one side. But then you would have to measure out and mark all those registration lines by hand, and that is usually done starting from one edge so they are not centered the way they are when my software generates the points. Thus if you flip a panel over when sewing they will not line up (whereas centered lines will). Moving a large paper pattern on and off the table between cuts is a pain too. Scrap is about the same since the panels are dimensioned to take up the entire width of the fabric roll, so there is no nesting done on balloon panels. The machine can also be used to pull the fabric off the roll and across the table, which would normally either require two people or a bunch of walking around the table to smooth out the wrinkles.

As with all CNC machines, the major time savings comes from the fact that while the machine is working you can be doing something else. So regardless of how long it takes the machine to do it vs. doing it by hand, you will be free to be working on something else during the 2+ minutes that the machine is cutting the panel. Now with a wheel type cutter you can really get the machine to work fast since you can run it at the maximum feed rate. Hot knife is limited to around 300 IPM max, since any faster an there is just not enough dwell time to cut through the fabric. A wheel cutter doesn't need dwell time though and will cut as fast as you can move it. Wheel cutters can also cut through more than one panel at a time, so by stacking panels you can REALLY cut down on cutting time. Wheel cutters require a special table surface which are kind of expensive though, and since I don't make balloons as a business I can't justify the cost. Perforated glass would be the ideal surface and really would not be overly expensive and would never wear out, but I don't know how one could make many small holes in the glass in order for the vacuum table to work. Melting with a laser maybe? If it could be done, that would be the ideal surface for all forms of cutting.

Probably the single biggest error avoidance benefit is eliminating the template plotting process, enabling your pattern data to go straight from CAD drawing to cutting without the potential for human error and all the tedium required to plot templates and cut them out. Currently I have the cut time for the largest size panel down to 2 minutes 20 seconds, so a full balloon could be cut out in about two days, or one long day. It really depends on the color scheme though. If you have a lot of different colors, there will be more swapping out of the fabric rolls and that will add time.
Last edited by Pyronaught on Wed Sep 25, 2013 9:53 pm, edited 2 times in total.

Pyronaught
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Joined: Wed Sep 25, 2013 5:33 pm

Re: Large Format Fabric Cutter

Post by Pyronaught » Wed Sep 25, 2013 9:40 pm

Another application I have in mind for this machine is the production of RC gas blimps. These are normally made from aluminized nylon or polyurethane films which are heat sealed at the seams. Thus I will need to develop a tool for doing the heat sealing, which will likely be a heated roller of some sort. When doing this by hand, you run into the same hassles as with building balloons, but then there is also the issue of maintaining proper pressure and speed when heat sealing. If you roll too fast, you don't get a good bond and the seam can pop, while if you push too hard, you can actually produce cuts in the plastic and the envelope will leak. The machine will be able to do that with much greater precision, resulting in more reliable seams.

Pyronaught
Posts: 9
Joined: Wed Sep 25, 2013 5:33 pm

Re: Large Format Fabric Cutter

Post by Pyronaught » Wed Sep 25, 2013 10:02 pm

If you want to see how painful the manual cutting method is, check out this build log for a 45foot long RC hot air blimp I built a few years back:

http://www.rcgroups.com/forums/showthread.php?t=1405313

I had to build a 48 foot long table just for cutting the panels, and this had to be outside due to not having the space for that long of a table indoors. I used video projection to make the paper template process more tolerlable, but even that is a pain and subject to inaccuracy. Then working outdoors with the wind blowing both the paper templates AND the fabric around was VERY frustrating. Even the slightest wind would cause problems. With this CNC machine I could have divided those long patterns up into sections and plotted registration marks on them to keep them aligned relative to the machine. I could have cut that whole thing out in just a few hours rather than days!

Here's video of that blimp actually flying:

http://www.youtube.com/watch?v=zIQ9CrbbOj4

WillAdams
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Re: Large Format Fabric Cutter

Post by WillAdams » Wed Sep 25, 2013 11:12 pm

Very, very cool.

Also inspiring since I've been thinking about cutting out leather pieces...
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
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jhllt67
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Joined: Fri May 04, 2012 1:57 am

Re: Large Format Fabric Cutter

Post by jhllt67 » Fri Oct 04, 2013 11:05 pm

Wow that is a beautiful machine. Very nice design.
Good idea on the old PC case for the electronics too.

Pyronaught
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Joined: Wed Sep 25, 2013 5:33 pm

Re: Large Format Fabric Cutter

Post by Pyronaught » Tue Oct 08, 2013 2:57 am

Here's the design I came up with for the controller which is based around a $300 Toshiba Laptop and a Logitech k400 wireless keyboard which has a touch pad built into it. Because the fabric cutter operates in a dust free environment, I decided not to spend the money on one of those waterproof washable keyboards and went for the cheapest thing that would get the job done in the smallest amount of space, which is the $34 Logitech keyboard. I know some are leery of using wireless keyboards around CNC machines, but I figure I'll try it and see how it goes. I like being able to put the keyboard on the table when typing or carrying it around to use as a poor-mans wireless remote when jogging from the other side of the table.

The laptop is mounted at an angle inside the cabinet in order to minimize the overall cabinet size and keep the laptop itself protected and hidden. Only the screen and power button stick out the top, and the screen can be folded down when not in use. The control panel uses an I-Pac keyboard emulator from ultimark.com to operate the manual joystick and push buttons. The e-stop is wired up to the controller on an extension cable, while the controller itself is located about eight feet away under the table. Since the controller is using an ethernet smooth stepper board, only an ethernet cable is required for connecting to the controller. The galvanized pipe pivot arm system might look a bit "steampunk" compared to the rest of the machine, but it is pretty low cost, quick to assemble, sturdy and pivots very easily. This machine barely fits in the room where it resides and the operator is forced to stand quite close to it when using the console, so having it be able to pivot out of the way when not in use was desirable.

The control panel uses nine push buttons and a joystick. The red and blue buttons on the right side toggle the pen and knife up and down, which would normally be the flood and mist controls on a mill. The colored square buttons are mapped to the g-code shuttle buttons rewind, play, pause and stop. The round white buttons are currently assigned to Home, Zero, Regen and a custom macro I wrote for cutting across the entire width of the table for doing cutoffs on a fabric roll. I may eventually add a shift button in order to double the number of function buttons to eight later.

A USB extension socket that came with the keyboard actually came in handy for extending a USB socket from the laptop to the outside of the cabinet, which is used with a USB memory stick for getting data in and out of the laptop. The laptop is running Windows 8 with everything stripped out of it including internet connectivity, virus checking, firewalls, windows updates, screen savers and all the other garbage that comes standard on a Windows 8 installation. While this was designed specifically for a fabric cutter, I think the design is generic enough to work for many other types of CNC machines. I'll probably build another one just like it when I make my mill next year.

I looked at a lot of options when designing this, including built-in computers, track balls, hula-point devices, fancy looking stainless keyboards and such, but opted for the simplest and lowest cost method. This took about three days to design and build, with a total cost of right around $500.
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