Open KNIT cnc machine, on Ultimate Sweater needle-bed as a platform.

[David Cofer]

After purchasing 200 SK120 needles, I discovered that the same needle is used in the Bond ultimate sweater machine. By incorporating this into the CNC Open-Source design we can eliminate one pricy part to have made. This Sweater knitting machine is manual, but the needlebed is Able to be used for our purposes, to build a Computer knitting machine that can spit out clothing.  This unit can be found readily available, is as cheap as just the needles nearly.

I am started in my build Using this platform as a starting point, Gerard suggested I join this group instead of starting a new one, as to keep sharing, using each other to "GROW" in knowledge and abilities.  My first job is to draw the Bond Needle bed in Sketchup.

Please check out my youtube videos to see who I am, what I have been learning and doing here in my shop. search ibewgypsie, user name.

I am a so-so arduino programmer, I am a so-so Visual basic programmer, I am a poor person with electrical-instrumentation-mechanical skills who owns Machine shop tools, metal working tools, welders, tubing benders and some other crafts I have learned over the years.. I am not the best at everything, I do not have a great big ego, nor a bad attitude to others, I am only putting forth how I am doing my build, I wish you the best in your build. 

My Pledge is I will help all others to the best of my ability as long as it does not impede my own growth and learning.  I wish to learn from you also.

[David Cofer]

   MY two Bond ultimate sweater machines we delivered, also with a extension board, so 4 sections (normal machines) plus the extension laid out on the floor is 85 1/2"  long or  217.17CM long?,  off ebay cost me $89 for a deluxe machine, two beds cost $29 (total $118 plus shipping). Each machine bed has 100 needles in it, empty spaces for 20 more needles on each machine. (two ultimate sweater machines = 240 needle spots with 200 needles included) Extension is 30 needle places, 30 needles included.  (those are more than $40 on ebay, not cost effective to buy them alone)

 

      THE two sides are labeled A, B.. connect with a metal rod underneath and a bolt between halves.

     needle spacing is 8mm between them, I started measuring the beds and my mitutoyo digital caliper died, the magnetic strip came loose halting that 3d drawing.

     MY wife wants these two machines assembled on a 2x8" board frame akin to a carpenters sawhorse for manual operation first.   (a losing argument to differ with a artistic wife) I know she will soon tire of the manual machine thou.  THESE manual machines are a lot of work, so I expect most the used ones are without much wear and the best Bang per buck.  I am bending a 1" tube on my bender for the end supports, so I can alter it and not have to remake that part.

[David Cofer]

Looks like each "block" of the ultimate sweater machine just clips together, you removed a rod from underneath, snap them apart. Each section of 20 needles is it's own block. THE end caps snap on, the red-yellow top rail just pushes down into the plastic extrusion.
  IF you put a parachute cord, sponge, or rope in under the extrusion it helps stabilize the needles and hold them in place.

  THE trolley-Keyplate, cams you change out to alter stitch length is crap, (it changes lead and lag by a lot of sticky guides) The trolley is begging for a cnc upgrade.  This will make a afghan or two, then go into a opposing Vee arrangment like your design.

  I kinda envision a "trolley" crawling down the unit, the yellow-red strip guiding it. A reprap gear belt positioning it, reading and placing needles in place to knit 2-color patterns or simulate dropped stitch hole patterns from punch cards??

     If there is money in the afghan blankets?? we might leave this one alone and buy more used machines.  I am pretty broke right now.

[gerard]

Great info David!

It's a very interesting approach but I think is easier to build it from scratch (if you have access to a laser cutter and a 3D printer of course), all the parts are already designed to fit and work together "properly". 

Using a Bond needle bed requires some redesign, the structure, the carriage, etc, although, It could be a very nice derivative and I'm pretty sure if you can adapt it correctly it you can achieve the same results, or maybe better ones. That needle bed has been refined through many years, way more than the one OpenKnit has currently.

[David Cofer]

Gerard, I built a "custom" Large 3d printer, still working the bugs out of it. I was so frustrated yesterday I was ready to pull it apart for parts and build a Delta printer.  It keeps shaking apart, moving too fast for the size-weight it is. (installed hardened bolts) The extruder was "not properly calibrated" and pushing too much filament and jamming. https://www.youtube.com/watch?v=Hk-C7akigQU&feature=youtu.be  NOW, I just need to put the home switches on and do some minor final calibrations.  Working one bug out at a time. My final desire is to 3d print models to "cast in aluminum"  here at my shop. Hotrod car parts, anything I want to make.  

I took a break to play with the Sweater machine, knitted some by hand, measuring the stroke, positions at which things happened.. made notes. I made a drawing of the keyplate-cam and measured stroke.

Yes, it is probably easier to make something "right" to fit the first time. Perhaps I will, this machine may stay a inline afghan machine..

Basics, Bond- USM knitting operation.

Positions of needles, Total width of working area, needle bed 73cm

1=All the way back against back rail, channel is 20mm wide

2=Back working position, channel 20mm wide, 40mm from back edge

3=Forward working position, channel 20mm wide, 60mm from back edge

4=Forward holding position, channel 10mm wide, 70mm from back edge

Cam Keyplate 3 operation, as measured with ruler.

1. trolley holds back on knit loop to allow needle to stroke in knit loop, cast on weights holds knit tight downward.

2.Cam moves needle 25mm out, opening latch, sliding loop past latch

3.Catches new yarn in hook

4.Cam moves needle 40mm in, closing needle latch on new yarn, pulling through previous knitted loop.

5.Cam moves needle 15mm out, relaxing yarn into back working position. Onto next needle.

[David Cofer]

200 Needles arrived from England, compared to the ones in the ultimate sweater machine the hooks are slightly larger, but compatible appearing. Paperwork states Knitmaster XKN8 120/120R, on packages it states KN8 in marker.

Supplier,
Bedford Sewing and Knitting Machines Ltd
Murdock Rd
Bedford MK41 7LE

tele 01234 217096 ?? strange number??

I took a photo to compare.  Posted it here.

[David Cofer]

THE experimental Afghan "cnc" printing carriage is on the frame, still needs tuning some..   https://www.youtube.com/watch?v=PNRQ86WO_DI
I need to buy a  book of stitches so I can program some fancy ones in..

David C

[David Cofer]

Machine is now functional, ON the design programming aspect of the project now,  I started out doing a Visual basic program that does simple "creation" of a Gcode file with boxes to enter 1st needle offset (X travel), Needle "finger" offset from Home position (Z travel) and of course the Y position to catch the needles with the yarn.

I went to "speed the arduino" up and discovered a "fault in the Marlin code". (Too many people made changes and lost track). I could not speed the travel time up till I found in the Marlin.cpp file a "limiting" speed variable, it was "homing" faster than it was traveling in a "non speed controlled move" ie: a G0 command.  I thought it was a over-whelming math problem (math calculations eating up all the cpu time) till I found the floating "fixed speed variable" there in that location.

My wife, who has all the common sense in our family also pointed out that the knitting "patterns" online and available all start from the center and go both directions, so now I am redoing the flow chart for the program to start writing the code.

To clear my head, (I have OCD) I may work on my cnc Sherline lathe project today.    CnC knitter is going at 1 second per needle now, that seems kinda fast but it is seven command lines per stitch.. and to do a 6' wide Afghan as we laid out this machine to do will take approxmiately six hours.   Also to do fancy clothing I must come up with a "Like Sergio" needle swapper.. I have to look at his machine again to see how he did it.. as the garment tapers off Needles must be swapped inward.
 
 In my old biker "head" I foresee sweaters fitting young shapely girls like they were painted on..  (comes from admiring beautiful women?)