Saturday, 18 February 2017

CNC upgrade progress - Current status

DIY CNC is just another way of saying "work in progress". Work in progress because I make constant improvements when I have a new idea which I believe makes it better in some way. However, my DIY CNC upgrade is now as ready as planned plus some more, and the currently ongoing improvements are smaller and smaller, so it is worth to note the current status.

Materials used


The material used (mainly, but not a complete list) is 45x90 and 30x60 aluminium extruded profiles, 10mm, 12mm and 15mm thick aluminium plates, hundreds of stainless steel screws, T-nuts and bolts mainly in 5, 6 and 8mm diameters. The total weight is approximately 80-90kg, including wiring, motors and all the electronics and power supply.

Increased stability


The actual CNC is desktop size but has its own feet, not just placed on a table. Originally on industrial rubber wheels, these feet are now lowered to some wooden blocks to give maximum possible stability. Earlier it was just standing on four lockable rubber wheels for ease of moving around but the drawback is that this is only good as far as low speed and acceleration is used. At higher speed and acceleration the whole machine was shaking, even when those wheels were locked, and this cause some accuracy and vibration problems, so I decided to lower the machine on four wooden blocks, making it more stable and less prone to shaking. The rubber wheels are still there but to roll around the machine on them is now a bit more complicated because it must be lifted first to remove the blocks and lowered down to the wheels before it can be rolled. This solution is better and actually necessary due to the fact that the acceleration values I have now are much higher than before.

Speed and acceleration


The maximum values I can get now is 10,000mm/min speed and 900mm/s/s acceleration. On my fairly small machine I found this crazy and scary fast, so I backed off a bit and set only 8,000mm/min speed and 700mm/s/s acceleration. I am using the same on all the three axes, so even the Z moves up and down at that speed and acceleration.

Short technical summary

 
  • Footprint (total area it is occupying in the room): 750 x 650mm
  • Table height from floor: 890mm
  • Y table size: 450 x 300mm
  • Weight of Y: 17,5kg
  • Working area: 310 x 270mm
  • Weight of X-beam: 13,7kg
  • Size of the X-beam (height x width): 500 x 540mm
  • Size of Z: 350 x 150 mm
  • Weight of Z: 8.5kg (this is increased due to a different, longer and thicker Z plate I use now)
  • Z clearance from table top: 160mm
  • Maximum speed: 8000mm/min
  • Maximum acceleration: 700mm/s/s
  • Stepper motor data: NEMA23 2.7V/phase, 3A, 1.6uh, 0.9 Ohm/phase
  • Stepper motor driver: DQ542MA
  • Stepper drivers PSU: 44VDC unregulated supply, based on a toroidal transformer
  • Motion controller: UC300ETH
  • Spindle motor: 24,000 RPM 65mm diameter air cooled 1.5kW spindle
  • Spindle motor power supply: Bosch Rexroth EFC 5610 VFD
  • Spindle RPM control via Modbus communication
  • CNC software:  UCCNC from CNC Drive (a Hungarian company)

A never ending story


It was a long journey to get where I am now, but it was a very interesting and challenging one. Have a look on the right side, scroll down to "My CNC story" section to know more about it. The links in that section are pointing to previous posts about the progress, all the way from just a pile of aluminium to now with a fully functional nice machine, with both failures and successes documented and photographed. You will find not only textual information, but also many images and video films showing the machine in different stages and details.

However, this is not the end, since for me, DIY CNC means continuous changes and improvements so it is a never ending story, which will last as long as I find this hobby interesting.

Future improvement plans and other activities


This is just a short list of what I have in mind or working on for the moment. The progress is good, but I will not give out any details yet. Also, priorities may change as time goes by.

V3-F1A


This is my own invention, or innovative solution if you want to call it that. It is a generic flash adapter for Nikon 1 V series cameras, allowing the camera to use standard flashes or radio triggers made for DSLR cameras. The very popular current version is called V2-F1A and of course the next one will be called V3-F1A or something similar. If you are interested in details, have a look on my blog. There are many posts about it. This innovative adapter was actually what started my DIY CNC project activity originally.


Anyway, follow this link for more details about this adapter:


https://adapting-camera.blogspot.se/2015/08/the-v1-f1a-is-dead-long-live-v2-f1a.html

Adding a 3D printer head


This is an idea I have but it is still early to say much about it. In my opinion it should be fairly easy to do it. My machine is now fast enough for the task but I have to look at it deeper. In any case, the Z is designed so that the spindle motor can easily be removed and replaced by a 3D printer head, or if I decide to do so, I could add the printer head by attaching it to the left side or the front of the spindle bracket, where I have a few drilled and tapped for optional accessory.

A high speed probe


Have all the macros written for this but need to develop the hardware and make a working prototype. I know how to do it and the work is started and the progress is good, but it is a parallel process and there are other things which pushed back the priority.

Shutter lag tester


This is a project connected to photography, not much to do with my DIY CNC except that like the V2-F1A adapter, my DIY CNC machine will be used for making it. I have a working prototype since several years which I have been using successfully but now it is time to make a commercial product out of it. This product is of interest for people and companies who technically test and validate cameras of different brand, either just out of interest or as a professional work. It measures the shutter lag with very high accuracy.

A new Z axis


In my opinion the Z can never be too good. I am happy with it right now, but I have several ideas about how to improve it even more. Never the less, it is very nice in my opinion and works well as it is.

A new X axis


This goes perhaps hand in hand with the Z axis. Maybe this is more important than the Z improvement. I think that if I can increase the rigidity of my X axis even more than my machine will be even more accurate and better, faster.

Replacing the steppers with servos


This is probably far off in the future, but would be fun to do it. I think that this change needs not only a simple replacement of necessary motors and drivers, but also improvement of the whole machine structure. I would be very disappointed if the huge increase in acceleration and speed could not be used fully because of structural issues, so the mass and the rigidity of the base, as well as the X beam, must go through a major upgrade before I invest in servo motors, but it is on my list of possible future improvements.

That's enough for now


I guess that the above, plus some other small things, will fill all my time for some years ahead. After all, this is just a hobby for me, and along with other hobbies and interests as well as a full time job and a family, it is enough for now.

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