DIY PC BASED CNC CONTROLLER.

[BBMNet]

Hello everyone.

I´m opening this thread as I was starting to mess another thread referring about automating a shop were multiple drilling is needed (Automate my shop with a CNC Driller machine).

While my intentions are really to help Rplummer3 i was probably being distractive to other users visiting his thread and as such he might not get all the help he needs and deserves.

In this thread I will present a simple control program capable to control 2.5 axes so that a platform (or a gantry) moves to position the tool and then this tool is moved down and up to perform the drilling cycle.

This new program is basically an improvement over a program I have been using to retrofit mechanical stitch quilting machines to control 3 motors but stripped down to only do that drilling job. That is, contouring will not be possible in the first stages.

Probably the most interesting thing to many is the fact that this program is entirely written in GWBASIC running under FreeDOS. Taking that into account its performance might be innadequate to many as the motors will move rather slow to what some are used to but those speeds are more than adequate to my original purpose. In fact I usually run the retrofitted machines at no more than about 80% of their maximum speed due to mechanical limitations.

The language used while it is possible to be translated into G code (I have the postprocessors both to and from) is the native language of my systems which has proved to be more easily understood by my clients. Please be tolerant about that. We are quilters and embroiderers, not mechanics. And as such the program we might end with may be useful to some but not to others. There is no tool compensation for instance. It´s more likely that those needing or wanting to work with flat surfaces will be those who will benefit from it.

The included file PRGCOMS.TXT provides a list of the current commands and mentions some to be added in the near future.

File DRLMAP1.TXT is a program to drill two rows of holes separated 10 cms apart from each other and also 10 cms separation from row to row.

The instruction I´m mostly interested to finish is CALL. If that command becomes operative DRLMAP.MIL will become DRLMAP2.TXT. Please note the size difference as the drilling cycle has to be written only once.

Doing so certainly takes some overhead time due to the CALL and END commands but in the long run it always proves to be better. That´s why we have canned cycles and subprocedures in many machines.

MIRRORY, MIRRORX & MIRRORXY are variations of CALL inverting the coordinates of the subprocedures. They are not yet contemplated to be finished.

Next time I will post a presentation of the FreeDOS system and an skeletal program to display the actual screen I will be using. Do not expect any fancy screen with 3d representations or any graphic image for that matter. It will be a simple text only screen.

The link shows a program I named TOYCNC that I posted here at that time (2013). It was intended originally for a small toy CNC mill that I was building with one of my youngest kids.



That program evolved into one of the lines of products I now sell and use to retrofit many machines.

Regards.

PS: please answer the one question poll. I need it to get an idea if this project is worth the effort and leave any comment in your replies.

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[BBMNet]

Hello.

This time I will be posting some pictures of the actual hardware used by this program and some pictures of the program as it works.

The full software package consists in the following:

1. TOYNC: this is the actual control program. It runs under FreeDos.
2. NCDATA: this file contains the basic parameters for the machine to run. Some are to be modified according to the actual machine where the system is to be installed.
3. COMPILER: this program takes a list of instructions written in the TOYNC language and generates a new file that is to be fed to the control program.

What I do in my machines is to have one USB stick loaded with a bootable version of FreeDos and upload there the control system. The RUFUS formatter is the perfect choice to prepare the USB stick.

Note: since NC listings can get very large it is convenient to have one USB stick accordingly.

Now please let me explain the pictures.

1 & 2. STP2ANA1 FRONT & BACK : these pictures show one of the control interfaces better known as breakout cards. This one uses one ULN2803 receiving signals from the main 8 bits of the LPT port and then signals the DIR- & STEP- lines of up to four SERVO or STEPPER drivers. The 5 input pins of the LPT port are used to receive signals like the REMOTE ON/OFF switch and the 3 microswitches at the HOME position of the machine.
The 4 remaining pins are used for output and taken by the wired DAC to produce an analog voltage from 0 to +10V in 16 possible discrete steps.

3. STP2: This picture shows a card identical to the previous one except the wired DAC is not included. As an example, this would be the choice for hot wire cutting machines.

4. TOYNC: This picture shows the actual screen of the control program.

5. XLSNAIL: This picture shows the screen of a program that includes a graphic representation of the pattern being processed. This particular program is only intended for demo purposes as BASIC takes to much time to execute when in graph mode.

As an old a technology as it may seem it is still used in many new machines like those in the hobby quilting market. The last two files contain the listings for the SNAIL picture depicted in XLSNAIL. SNAILTXT is the original file as used by one quilter brand. SNAILOEM.TXT is the converted file to the language used by TOYNC.

A basic bill of materials is next. HEADERS & SOCKETS are used for the connections. Resistors are 1/4W or 1/2W 5%.

1. 1 piece of perforated copper clad protoboard. Check how the circuit is assembled so that you will know how to cut it. I suggest assembing first and then cut. The excess area helps for better heat dissipation specially when tinning.
2. 2 pieces of 3 circuits.
3 1 piece of 4 circuits.
4. 1 piece of 5 circuits.
5. 1 piece of 7 circuits.
6. 1 piece of 9 circuits.
7. 1 piece of 10 circuits.
8. 50 pieces of female connectors.
9. 1 piece 8 pin DIP IC socket.
10. 1 piece 8 pin DIP IC socket (optional for DAC).
11. 3 pieces 0.1 uf/16V or higher voltage ceramic, monolitic or tantalum.
12. 1 piece 470 uF/16V electrolytic capacitor.
13. 5 pieces of 3900 ohm resistors.
14. 2 pieces of 5600 ohm resistors.
15. 1 piece of 4700 ohm resistor.
16. 1 piece of 10,000 ohm resistor.
17. 1 piece of 22,000 ohm resistor.
18. 1 piece of 47,000 ohm resistor.

Miscelaneous materials:

19. Rosin core tin-lead solder wire or equivalent. 65/35 alloy is preferable but 60/40 will do nicely,
20. Tinned AWG22/24 stripped copper wire for the connections.

Tools:

21. Cleaning flux. Apply this to the back of the protoboard to clean it. It should look pink when properly cleaned.
22. Ink eraser. Vinyl is preferable. Use in case of stubborn rust stains in the clad of the protoboard. Reapply flux thereafter.
23. Thin tip solder iron. Station type is preferable but most hobby pencils will do. Avoid soldering guns as they are too hot and too wide so that the copper may get loose from the protoboard.
24. Soldering sponge to keep the tip of the iron clean. This is most important during the tinning of the protoboard. Remember to keep the sponge wet.

Please take a good look at the pictures. You can wait for the diagram if you want but as you can see it is fairly simple. Other than the conecting cables there is no other electronic card or componen needed by this system. I believe that the beaty of it. Its simplicity.


Bye for now.