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did you weld the NSK's on ????????????????????????
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This is my very first CNC machine. It measures about 5' x 4'. The z-axis is about 3.5 to 4 feet high. I originally designed the bottom frame for a 2.5 feet width, but decided to make it 4' (which is the reason why it looks funny). I used mild steel and did all the welding myself since the advice I got was to make it as rigid as possible. I am using THK rails/bearings for the X & Y axis. Any suggestions is appreciated.
did you weld the NSK's on ????????????????????????
Stevie,
I used the same method as another user used for mounting the THK bearings/slides onto the frame. I used a long piece of 1/2" x 1" x 56"L (approx.) mild steel flat bar. I aligned the THK slide over the flat bar (clamped together) and used an inexpensive "punch set" to mark drill holes on the flat bar. I then drilled holes and tapped the holes. I then screwed on the THK bearings/slides to the flat bar and welded the flat bar to the frame. Some advantages to this method is the THK slides are very securly mounted to the frame and will not move or be misaligned under load (it is very sturdy). One dis-advantage is that the two THK slides must be parallel before welding or you will miss things up. I used some jig device I made for aligning things. On my next CNC frame project, I will probably just use a piece of mild steel "channel" and weld it to the side of the frame and drill holes to mount the THK slides. This way I can make small adjustments to make things align well.
Thanks,
Why did you make the Y axis so high?
A little more space between the bearing blocks may have made it a little sturdier.
Will it sit on the floor like that or on a table at some time?
Looks good, keep going.
E
I wish it wouldn't crash.
I had originally made the cnc frame much smaller to fit in my garage. However, I bought a small shed and decided late in the construction process to make the x and y axis full length (the length of the THK slides). The cnc frame is still sturdy since I am using thick steel and the base is heavy. The 2" x 3" beam of the y axis measures 3 feet high. I did not know how high to make it and I plan on attaching a 5th axis head to it. It was best to have more y axis room than needed in case I needed more clearance. I plan to put it on a self-made table so I can store things below the table to maximize space in my shed. This is my very first CNC machine and some mistakes or design flaws will happen.
Thanks,
It's just the photo res; I thought you had welded them right onto the frame
might I ask just what you payed for the slides; as i just got a quote for NSK's and I'm still on the floor
Stevie,
I bought the slides more than a year ago at ebay. I cannot remember how much I paid for them.
Also, I have a question for anyone. I am putting together my z-axis. I am worried about the heavy weight of my z-axis assembly. Short of getting a bigger stepper motor, is there a way to better handle the weight? I was thinking of using some kind of spring that would significantly make the z-axis assembly lighter. Has anyone seen a spring used to reduce the load from the motors?
Thanks,
add a counter weight; use cable or chain going over pulleys to change the direction by 180dgr; then the weight will help the steppers; this just the same with most bigger CNC's or even old time horizontal boring machines
I have a spring below the Z-axis to counterweight. You need a fairly long one to keep the force relatively constant over travel. It is kept in place by a thin steel rod inside the spring. Also take care that its not (nearly) fully compressed when Z is lowest, because the force increases sharply then.
John
few people use gas- charged cylinders for counterweight force. They are constant force and some are adjastable. They also come in different lenghts.
Maybe this tread should be moved to appropriate location that way you'll get better responses and suggestions, IMHO.
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