Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: John Mac on November 24, 2008, 08:33:56 AM
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Hi All
An exciting time.. Over the last couple of years I have kept an eye on Mach 3 from the numerous forum posts both here, the CNCzone and on You tube. Mach 3 has become irresistible.
I work in the rag trade so for me the use of CNC will be a little different to metal working or routing. My interest is in stitching, while the overall system accuracy for stitching is a lot less than precision machining. There are other problems that must be overcome. The system I intend to create will be in the form of large Router table. With the added complication that the sewing axis will require 2 synchronized drives to drive the needle and the hook and thread bobbin separately, (The mechanism under the table of the machine) a simple 1:1 ratio but not constant speed and with a speed range of 500 – 4500 rpm, and this speed must be relative to the tool path speed. Not an easy task from my enquiries so far. Yes it can be done mechanically but not without a lot more hardware.
My previous experience was retrofitting a CNC sewer. It took a lot of time. The hardware had to be hacked to enable user programming rather than going back to the supplier it was encrypted, or rather obfuscated. (Not uncommon for textile machinery) I also wrote a VB program to feed it with code its native code not G code. The software reads a DXF file using polylines and converts it. The math routines may come in handy again.
Today I would chuck out the hardware and start again.
I would be pleased to hear from any fellow Rag trade members, it would be fun to discuss some of the issues that relate to stitching.
Cheers
John Mac
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Hi John,
Welcome to the site. I haven't noticed anybody doing anything applied to a sewing machine but
go ahead and post and see if Mach is an application which you want to use and learn more about.
Your free to post in other threads now.
RICH
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There is one company that makes and sells sewing machines that run Mach, do a search for magic quilter and you may find something. I doubt if they will give you much info though as obviously it is a commercial venture for them but there are videos of it in action so it might give you some ideas.
Hood
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OK its Handi Quilter, heres a link http://www.machsupport.com/forum/index.php/topic,6939.0.html
Hood
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Thank you Rich and Hood you guys are quick to respond!
I have been working on the calculations for the x axis.
It will need to be about 4000mm wide
Made from 2 lengths 250 x 150 x 5 RHS spaced 300mm and joined with 150 sq tube and the ends welded over and fully joined.
There will be 2 type 25 rails mounted on each beam giving 4 in total.
Compared to machining or routing sewing has the need to have a tool on the bottom and the top of the cloth hence the need for the large vertical O frame to pass the work through.
I calculated the deflection (Simply supported at the ends only) to be about .211mm with a 40kg load in the centre (The moving head) and the distributed load imposed by the rails about 10 kg per metre. The frame has to be really stiff the load is small but there will be resonance. I wish I had better software, and a younger brain.
Not bad for such a large span.
I used a handy tool to do a quick deflection calk called Beam boy.
I found it at:
http://www.engineers-international.com/freeshare.html
It works quite well I am sure there are more advanced tools so if you have one please post a link.
250 x 150 x 5 RHS weighs about 29.9 kg per metre add to that the rails and the sewing head and we are moving about 350kg to 400kg
For a standard 4000rpm sewing machine we need a feed rate of about 233mm per second max. That is a fair amount of weight to push around; it will need some meaty drives. (I think I will drive it in tandem from the ends). Unlike metalworking the positioning accuracy required is around .5mm, (approx 20 thou imperial).
The frame with the sewing heads not included there we need a couple of thou max error along the x axis.
Sizing the drives is not going to be easy for me. If there is software out there in cyberspace to assist I would really appreciate hearing about it.
Usually the first iteration of a new design is doomed to be changed, but so far its looking good.
Cheers
John Mac
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Might be worth looking into the Alu extrusions for the machine structure, might find them by googling Bosch Extrusions, they are very rigid and lighter than steel for more strength and will allow you to use lighter sections. Problem is they are not cheap so might not be worth it.
Look up some of the servo makers sites, most have sizing software. Think Kollmorgan have some, servosizer rings a bell.
Hood
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Hi Hood
The catch is for a given section size the Aluminium will be lighter but the deflection will be higher. Most of the time by the time you have the stiffness sorted strength looks after itself. The depth of section would need to be increased to gain the same deflection number.
The other catch is the straightness of the material when I checked the steel supplier the straightness from the mill is specified as within the section length divided by 500.
That means 4000mm /500 = 8mm possible camber. That needs to be corrected before the rails are placed.
Unless the Bosch rails were perfect they would have to be machined also.
Careful inspection at the steel suppliers yard should find some better than standard. (If they will let you in!!)
There is a jobber near us that has an Elgamill I will have to contract out this part
http://www.factoryhub.com.au/DesktopDefault.aspx?ItemID=881026&TabID=202700
Gee I wish I had one of those, very nice.
The rest I can machine myself.
So the frame can be mounted and machined for the rails.
If straight stock is not available then 200x100*9 could be used to allow machining the mounting point That has a deflection of .159mm Still OK and only 7kg metre heavier slightly better than the 250x150x5 section above actually.
Another way would be to weld thicker pieces on and machine those.
All these compromises are a bear.
Cheers
John Mac
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The Alu I am talking about is the Bosch Extrusions, not just RHS alu and also from the stuff I have seen it is very accurate. This is the stuff I got bits of when a local company shut their operation, http://www13.boschrexroth-us.com/Framing_Shop/Product/Default.aspx?category=10109
Dont know the cost but probably is quite high they used it in all of their custom inhouse machines.
Hood
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Thank you Hood
The Bosch extrusions are nice.
Alas the straightness is not quite there.
http://www13.boschrexroth-us.com/catalogs/mge50/sections/section%2016.pdf
Page 2. Lengthwise profile straightness tolerance
That shows an error of around 2 mm using a 2 metre lenth, it would be a lot more using a 4 metre length.
Using the deflection calculator Bosch provide on their site. For a 4 metre length of 100 x 200mm section I got .39mm compared to the .159mm for steel (but overall a lot lighter frame)
Easy cheap and accuracy can never appear in the same sentence.
Still there must be another way: Maybe precision laser cut plates assembled into a box frame and welded? Maybe with small slots cut in line with where the rail would sit to enable you to place the rail against the edge for location. The laser could cut the mounting holes as well.
Has any one tried that?
Cheers
John Mac
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Dont think ywelding would be the answer, not much hope of keeping accuracy if you were welding the seams.
Hood
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There will be 2 type 25 rails mounted on each beam giving 4 in total.
Is that linear rails you are talking about? If so is accuracy of your steel frame that important? Would have thought the normal practice would just be to shim the rails at each mounting to keep them true.
Hood
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John,
Just quickly read your postings to get a feel of what your up to.
For the frame start with a depth of section equal to 1" per linear foot of distance ( sorry you can convert ) then
check for deflection or work backwards and find the section based on total anticipated load and see what
I,S,R you need. Stiff doesn't mean resonant free. Beam Boy is fine but haven't used it in years for static loading. From a resonant point of view, nothing is better than weight as that drives the value down and you should have basic design done before you / or if someone would do analyzation. You weld up a frame, besides distortion from welding which you can kind of control ( Hood welds i think ) , after your are all done and if you machine without stress relieving it just can / may go wherever to some extent. Maybe dummy pieces on top of the frame which can be machined post attaching to frame fabrication may be a better choice. The piece is rather large so machining is not going to be cheap even for a few facing cuts.
You can analyze for motor requirements / torque required using a number of free programs. Mitsubishi, Superior Electric, Parker, and Danaher Motion all have one just to name a few.
The first step to getting a good sewing machine to have the wife hem the pants before staples, chewing gum, or crazy glue is used instead of thread. ;)
RICH
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Just reflecting on what Hood said, as I agree, and would be cheaper. Then epoxy the rails to the bed after
leveling / installing to tolerence you want.
By the way, cross brace the bottom, corner to corner, to keep bed from twisting.
RICH
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Hi Rich
I don’t think I can avoid welding and then getting the rail mounting points machined.
Attached is the solid model I am working with. It has not been optimized yet. Just a sketch to get the feel of the issues involved.
It shows ground shafting as the rail system.
I recently found a better deal with a Taiwanese rail so will use that instead.
It is a bit over a third the cost of a Bosch “Star” rail.
http://www.hiwin.com.tw/Products.aspx?type=gw&subtype=gw_e2
Type 25 is a (Most of the time) reference to the size class of linear rail. When you check the specs most manufacturers have a system that uses the same mounting holes and overall height. The load capacity varies as does the quality and accuracy. You can not mix and match rails and runner blocks between manufacturers.
Cheers
John
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Looks like you plan on moving the machine back and forth and have the rug stationed? What about some thing like this were the rug moves and not the machine:
http://img.hisupplier.com/var/userImages/eachsun/20071128/122810.jpg
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Hi Dennis
Thank you for your thoughts.
The reason is floor space… These machines are big. you can save say 4x5metres = 20 square metres…. about 220 square feet by not moving the work.
The application I am working on is not quilting although the machine would be quite capable of doing it.
I did a lot of browsing with a search tool called Alibaba
http://www.alibaba.com/
Quite good for industry specific searches of the net
Attached here is a couple of machines that do not move the work:
Both made you know where.
Cheers
John Mac
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Hi All
An exciting time.. Over the last couple of years I have kept an eye on Mach 3 from the numerous forum posts both here, the CNCzone and on You tube. Mach 3 has become irresistible.
I work in the rag trade so for me the use of CNC will be a little different to metal working or routing. My interest is in stitching, while the overall system accuracy for stitching is a lot less than precision machining. There are other problems that must be overcome. The system I intend to create will be in the form of large Router table. With the added complication that the sewing axis will require 2 synchronized drives to drive the needle and the hook and thread bobbin separately, (The mechanism under the table of the machine) a simple 1:1 ratio but not constant speed and with a speed range of 500 4500 rpm, and this speed must be relative to the tool path speed. Not an easy task from my enquiries so far. Yes it can be done mechanically but not without a lot more hardware.
My previous experience was retrofitting a CNC sewer. It took a lot of time. The hardware had to be hacked to enable user programming rather than going back to the supplier it was encrypted, or rather obfuscated. (Not uncommon for textile machinery) I also wrote a VB program to feed it with code its native code not G code. The software reads a DXF file using polylines and converts it. The math routines may come in handy again.
Today I would chuck out the hardware and start again.
I would be pleased to hear from any fellow Rag trade members, it would be fun to discuss some of the issues that relate to stitching.
Cheers
John Mac
Hi John,
My name is Larry Lamb, and I have developed a cnc quilter system using mach3 as the controlling software. My wife uses it to make quiltes for other folks and family members, and it has been a really fun challenge. I am using the viking megaquilter with two stepper motors to move the system, and a low voltage dc to ac relay to control the needle. The entire system is controlled by an HP small format computer with two gb of memory and a 80 gb hdd. also have an external drive with 500 gb of space for storage of patterns. I am working on programming for additional control of external devices to control the takeup roller in the throat of the sewing machine, using the arduino boards to control this activity, and magnetic detection to command movement of the Y axis carriage and the takeup roller.
If you have any questions, I would be happy to assist.
Larry
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Hi Larry
Thanks for your offer of assistance.
In previous Life I bought a commercial CNC Quilter Resta H220 for my business. It was fairly old although the control system worked perfectly using a Z80 based processor. Interesting to think about that...... a few cards loaded with 7400 series IC's and the Z80 instruction code in Eprom. (Naturally I backed that up just in case). Over the 15 years we ran the machine it occasionally would develop a fault. No problem every part on the boards were easily replacable. No Surface mount stuff (Now so small it is almost dust) No multi layer boards with unfindable broken tracks. We never had to buy a replacement board.
The minus was It used a proprietary instruction set to store programs and the instructions were obfiscated I guess they did not want to make it easy..... there was a PC based "Programming system" available for huge money or a hand programmer that was error prone. not a good option. Or you could order programs from the factory for a fee and a delay of a few weeks. the programs were delivered on "Eprom" UV erasable static ram.
I decided to make a project of it and design my own programming system via Autocad DXF into a CAM converter written in Visual basic that converted the DXF file into Resta Instruction code. It sounds easy......well it is not however after about 6 months research it was done!
And the patterns produced are dead accurate unlike the results from the hand teach mode programmer that was NQR.
I don't run the machine any more however I still have the programming system.
Cheers
John
PS:
The machine below is not the same machine but very similar, Except my machine was enlarged. We cut the main frame and made it 1200mm wider and rebuilt the rest of the machine to match it was a bit of a beast requiring 8000mm x 6000mm of floor space.
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The following thread needs some courage to read but having worth of information including free Gcode generator for embroidery work. Larry has also worked on the quilter and can share information on that if asked.
http://www.cnczone.com/forums/cnc_wood_router_project_log/57404-diy-_cnc_embroidery_machine.html
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I'm looking for some one that has used Mach to do Sowing, I'm looking for someone that has got the problem of stitch to feed rate solved
I understand that sewing is unique and most of the work is being done on milling and turning
I'm sure that I'm not the only one that wants to build a Sewing ( quilting ) machine and i'm looking for someone that is willing to share
what they have done to solve stitch length and programing......
I have a workig 3 axis Mill running under Mach. .... and have 2 Husqvarna Viking Embroidery machines, I have Husqvarna Viking 5D programing software, so I'm looking how to control the machine ( dfx-G-coe who knows )
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HI about a year ago I wanted to know how to computerize a quilting machine using Mach 3, I hadn't heard anything from sometime, so I jumped in to it.
I got a 18 inch quitter and stated building the hardware using belt drives, I found a good cam soft ware that outputted G-code from quilt libraries “quiltcam" and then wrote a visual basic program to add all the auto lock stitch, start and stops. I also added some pokey and relay to interface with the stitch regulator on the machine and it new beautifully.
Did a bunch of quilts and found that I had to move on so I have now sold the machine….. It was a great project and fun for a while, but I still like the 4 axis mile and 3d printer to keep me busy.
Going to build a 48x 48 inch router this spring….. Thanks for just giving my project a thought.
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Hi Jonjell,
I am sorry you did not receive any interest in your 2013 posting :'( but it sounds like you have succeeded without any assistance from others here :)
I think many of us have tried using Mach3 for quilting and embroidery but, at one stage or another, have all come up against the 5 stitches per second barrier (4 stitches per second in my case).
Tweakie.
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If you use the stitch regulator that is used in most machine for manual quilting it is very easy, the stitch regulator detects that movement and speed of travel. So all I had to do is modify the g-code to turn on the stitch regulator and provide the path. It didn’t make any different how fast or slow I moved I had evenly spaced stitches
http://www.jonjell.com/Quilting/machinerunningmovie.html
I just needed the bedroom back ( well the wife wanted it back)
jonjell
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Informative thread.
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And I am still around
A conventional "plain" sewing machine controls the stitch length by the movement of the "Feed dog" that pulls the material from underneath in short strokes. Best you study an actual machine to see how it works the length of stroke can be adjusted by a knob or lever in the sewing head. A few "walking foot' or "needle feed" machines also feed from the top but that is another story.
A typical plain sewing machine operates at around 5000 rpm (equaling 5000 stitches per minute), however quilting is thicker than say shirt fabric and it is normal to reduce the speed to between 3500 and 4500 RPM. You reach a point where thread breakages become an issue, there is too much friction and the needle can become so hot it will melt the thread.
However a frame quilting machine head mechanically or CNC driven does not have mechanical feed dog. To control the stitch length you need to match the feeding speed to the stitching speed using a ratio that that gives the right stitch length.
These days most quilting machine designs use a moving head in an XY frame, the fabric in its frame stays still, mechanically considerably more complex, the benefit being a greatly reduced machine footprint.
The machine will be heavy with a large moving mass even for a small design, This means that unlike a manually driven machine where the material is stationary when the needle penetrates the fabric the machine will be moving and so will the needle, this can be alleviated a little by a the foot on the machine that holds the fabric down the "Presser foot" but there will be some movement. in spite of the movement the system will work as long as the stitch to feed ratio is not too big. Typically the stitch length at 3500RPM can be around 3mm. Longer stitches will require slowing the machine down.
For any given material, thread and machine there will be a sweet spot, Its not unlike metal cutting in that respect.
On The Mach 3 side the objective will be to maintain a constant feed / stitching speed ratio. at any feed rate, if this is not done the stitch length will vary.
I cannot imagine Mach could handle moves on a stitch by stitch basis except at slow stitching speeds? However it would be a good feature for things like "Back tacking" at the start and end of a line of sewing. Some sewing heads can also trim the threads off at the start and end of a line of stitching that would have a subroutine (It has to back up the line it just did)
Lastly sewing machines are not perfect there are too many variables thread will break. A means of reversing the program back to where the break was and a little past it will be required.
It's been a while since I thought on this I wonder if Mach4 is better equipped to handle CNC sewing?
Regards
john McNamara
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It's been a while since I thought on this I wonder if Mach4 is better equipped to handle CNC sewing?
Hi John,
I think there is perhaps only one way to tell ;)
Tweakie.
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I think the way to do this is to build a square truss. Use 4 - 40mm square Bosch, or my preference Palleti rails. Take 25mm round tubing and flatten about 25mm long with an 8mm hole for a bolt into the slot of the 40mm rails. Then zigzag bend it for the diagonals of the truss. When you assemble it you simply adjust a pair of rails for exact spacing and straightness. Make two straight pairs, then assemble into a square. Some corner to corner diagonals inside the truss make it torsionally stiff. Very light, very stiff, very straight.
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For the control side I would divide and conquer. Use Mach 3 for the pattern motion in X and Y. Use an Automation Direct BRX plc to control the stitching motor synchronization. High speed inputs from two quad encoders on the X and Y axis can be summed to give the PLC the linear speed. Then the PLC can use the high speed outputs to drive the two motors in synch with the linear motion speed.
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Great thread
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I followed this http://sewingmachinespoint.com
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Hi All
Here may be the answer to all those wanting to build any sort of CNC sewing machine!
The program path needs to be reversible because the thread often breaks when stitching requiring the machine to be backed up to before the break, then rethreaded. and finally restarted, overlapping the end of the first run in the trade called "back tacking" and the restart.
The controller needs to reverse, and this one can! I am sure the 35000 program segments will be more than enough to do this sewing paths are very simple. It needs to be a simple push button function with the path reversal shown on the Display screen.
Thanks to the post below this may be the solution.
I stumbled across the You tube Channel "Applied Science".
https://www.youtube.com/watch?v=rpHYBz7ToII (https://www.youtube.com/watch?v=rpHYBz7ToII)
The post describes Building an EDM Drill.... quite interesting, however I do not wish to build one.
However the builder just happened to mention that the CNC controller he used was able to feed in reverse back up the program buffer as well as forward. I nearly fell of my chair!
So I emailed the KFLOP company and promptly got the following response.
Quote
Yes our KFLOP Controller has the ability to perform hardware feed rate override (FRO) including negative feedrates. See here. KFLOP has a motion buffer that can contain up to 35,000 coordinated motion segments. This is typically many seconds of motion depending on the complexity of the path and speeds. So it is possible to reverse this amount of motion. When using Feed Hold in our KMotionCNC program two buttons (Forward/Reverse) are enabled which are coded to command the Feedrate to +0.2 and -0.2. See this video. the important bit is towards the end.
https://www.youtube.com/watch?v=uPQfGeydsDM (https://www.youtube.com/watch?v=uPQfGeydsDM)
As far as I know Mach can not do this? Can anyone confirm?
End Quote
Regards
John