This being my first Instructable, please forgive me for the lack of photos during the build as I only decided to post it on here after the project was completed.
The reason that I chose this project was that I have been interested in trying machine embroidery for some time, but the thought of spending a lot of money on a dedicated machine and then finding that it was not for me didn't appeal. Being a handy fellow and liking a challenge I decided to build my own.
After a scour of the internet it was clear that I was certainly not the first to try this, but I also found it hard to find any real success stories - challenge accepted!!!
Step 1: The Donor Sewing Machine
The reason I chose to use a Singer 15 was mainly because they are; very cheap, reliable, and available.
I ended up buying the Sphynx design because it looked good :)
The first step was to ensure the machine worked correctly for sewing. So I gave it a quick lube and check over, threaded the bobbin and needle, adjusted the tension, and it worked well at all speeds.
Next I removed the feed dogs from the needle plate to ensure that the embroidery hoop would be able to move without restriction, and replaced the belt drive pulley with a toothed pulley and belt connecting to a NEMA 23 stepper motor.
Then I mounted the machine onto a piece of MDF that could be connected to the X/Y axes.
This is all the modifications that were required on the actual sewing machine
Step 2: X/Y Axis
For both the X and Y axes I decided to use linear rails.This reasoning behind this was; cost, stability, the ability to customise/modify the length of the X Y travel at a later date should I need to.
Belt drive was chosen due to; cost, the ability to cope with slight misalignments, ease of adjustment, and simplicity of installation.
The two rails for the X-axis were screwed onto a piece of MDF, with a piece of flat press steel connecting them. Then the Y-axis was mounted onto the flat press, with a small piece of aluminium to both clamp the belt, and hold the embroidery hoop (Various size BROTHER hoops purchased from Amazon for ~£25:00) . Skateboard bearings were also mounted onto the ends of the Y-axis as belt pulleys, and one end of the X-axis as another guide/pulley
Next I fabfricated some mounts and installed NEMA 23 stepper motors on both axes.
Step 3: Control System and Code Generation
For the control system I use Mach3 controlling 5a stepper motor drivers.
There are many tutorials on the web, and here, about how to setup Mach3. So I won't go into any detail on that, but in order to convert the embroidery files into G-Code I did manage to find some awesome sofware written by a guy called Khalid on CNC-zone. Thanks Khalid!!!
This software converts files from the Tajima embroidery format into G-code suitable for Mach3, I found it was sometimes necessary to delete a few lines from the beginning and end of the generated code but other than that it works really well.
For the embroidery designs, it is possible to find many generic free ones on the internet, or use online generators, or software such as Wilcom to create your own.
Step 4: Conclusions
As you can see from the video the machine works quite well.
The downsides that I have have discovered with this design are:
Thread tension on the Singer 15 is not particularyl consistant. This can cause thread breaks if there is a big jump from one part of your design to another, or bobbin thread showing in your design (if you use a different colour bobbin thread to your top thread)
The whole system is a bit noisy
Compared to a modern embroidery machine it is relatively slow. For sure changing the motor drive from 2:1 to 1:1 or more would greatly improve this.
On a Positive note:
It can be a cheap project that functions really well
Easy to build and maintain
So far it has proved reliable
With a custom hoop and different rails you could increase the Y-axis to produce some really big designs
For further improvements I would like to try this with an Industrial sewing machine. I think then you could really make it fly.
I hope this has been of some use, and if you have any questions, ask away.
Note:- NEMA 23 stepper motors are total overkill for this. I have several other CNC toys that use NMEA 23's and it made sense for me to have the all the same for interchangeability.