I was thinking about running copper pipe through a mini refrigerator to make an air dryer. Have a small dropout tank after the refrigerator. But I scored a refrigerated air dryer off of Craigslist and that was the end of that. But I think it would work for a hobbyist just fine. Having a tank of water inside with the pipes running through it would make it better by storing the cold so to speak. That is the same principle on the one that I bought.
You Big Dummy!!!!
- Thread starter Runs With Scissors
- Start date
Hello,
great result once you figured the ground connection !
This is one fine piece of equipment you have there. Would you mind posting a picture showing the whole CNC cutter and the rough dimensions?
How do you start the cut and how does the movement look like? Maybe by modifying the movement you can improve the small holes. So start in the centre and spiral outwards and maybe doing two full circles instead of one.
Alternatively you could try to put an egg shaped hole into the CAD system for the small holes, basically compensating for the error in the cut.
But having said that: I would be very happy having a machine like this producing those results.
Kind regards,
Hugo
great result once you figured the ground connection !
This is one fine piece of equipment you have there. Would you mind posting a picture showing the whole CNC cutter and the rough dimensions?
I am not sure but I feel the big holes are the same as the small holes, only the bigger diameter covers up the imperfections.
How do you start the cut and how does the movement look like? Maybe by modifying the movement you can improve the small holes. So start in the centre and spiral outwards and maybe doing two full circles instead of one.
Alternatively you could try to put an egg shaped hole into the CAD system for the small holes, basically compensating for the error in the cut.
But having said that: I would be very happy having a machine like this producing those results.
Kind regards,
Hugo
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Runs With Scissors
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Ohh SNAP!
Thats an awesome idea for the QC Tool post adaptors.
I was thinking of having my SIL print some of these, but now I am torn.....Damn it man!
Runs With Scissors
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L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
Yep, and thats part of the problem. I have to finally make a "decision" and then follow through.
My hobbies are quickly surpassing(have surpassed) my time off and budget...hahahah
Good problem to have I suppose, keeps me busy and thinking.
For now my "air dryer" set up should be "good nuff". It might cost me some amount in consumables, but it should be "better than nothing".
I have considered making the "refrigerator idea" though.
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Runs With Scissors
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L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
Thanks for the supportive comments.Hello,
great result once you figured the ground connection !
This is one fine piece of equipment you have there. Would you mind posting a picture showing the whole CNC cutter and the rough dimensions?
I am not sure but I feel the big holes are the same as the small holes, only the bigger diameter covers up the imperfections.
View attachment 145417
How do you start the cut and how does the movement look like? Maybe by modifying the movement you can improve the small holes. So start in the centre and spiral outwards and maybe doing two full circles instead of one.
Alternatively you could try to put an egg shaped hole into the CAD system for the small holes, basically compensating for the error in the cut.
But having said that: I would be very happy having a machine like this producing those results.
Kind regards,
Hugo
I have a program called "SheetCam" that "Auto-Magically" takes care of the cut patterns, and it has options to "lead in" and "lead out" the cutter, depending on the situation.
Smaller holes just tend to be "more problematic" due to the kerf, and other variables like consumable wear, grounding problems etc.....
I am certainly no expert, but I am "muddling through".
I will take some pics of the set up today with the dimensions and post them.
Lil Foot
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Russell King
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You might want to just consider locating the center point of the hole and just gouge or pierce the metal. Then use a (step) drill bit to get the hole size needed.
That can eliminate the hardness of the steel making it difficult to drill holes out to make them round and the drift in location when you use a twist drill in a non round hole
Runs With Scissors
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Yep, I think this is a good idea in future parts if I can't figure out how to "cut" them more accurately.
.GreensvilleJay
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normally blow 'start' hole just inside then move to final diameter. gets to be 'tricky' when stepping motors are used, easy with servos though.Hello,
great result once you figured the ground connection !
This is one fine piece of equipment you have there. Would you mind posting a picture showing the whole CNC cutter and the rough dimensions?
I am not sure but I feel the big holes are the same as the small holes, only the bigger diameter covers up the imperfections.
View attachment 145417
How do you start the cut and how does the movement look like? Maybe by modifying the movement you can improve the small holes. So start in the centre and spiral outwards and maybe doing two full circles instead of one.
Alternatively you could try to put an egg shaped hole into the CAD system for the small holes, basically compensating for the error in the cut.
But having said that: I would be very happy having a machine like this producing those results.
Kind regards,
Hugo
GreensvilleJay
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BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
why, is based on 'how they work'..
'steppers' move in discrete 'steps' by pulses from the 'computer',one for 'x' and one for 'y' positions. even with 'hires' steppers you cannot draw perfect circles. Such is the nature of the beast. They also don't move the same distance CW vs CCW, unless someone's done some clever coding for the 'driver'. This involves a lot of testing, data collecting,'curve fitting'. stuff that low end CNC machines don't have. Now in a lot of parts the end user doesn't need 'mil-spec' precision, so not a big deal BUT if you're making parts from 4 x 9 ' sheets of steel and need them cut FAST ( time is money), you need to be able to program for speed and accuracy.
The hole in post #22 shows there probably is a problem in the software( the rest of the circle looks ok... ) but if it's not 'mission critical', not a big deal BUT it can be seen.
'steppers' move in discrete 'steps' by pulses from the 'computer',one for 'x' and one for 'y' positions. even with 'hires' steppers you cannot draw perfect circles. Such is the nature of the beast. They also don't move the same distance CW vs CCW, unless someone's done some clever coding for the 'driver'. This involves a lot of testing, data collecting,'curve fitting'. stuff that low end CNC machines don't have. Now in a lot of parts the end user doesn't need 'mil-spec' precision, so not a big deal BUT if you're making parts from 4 x 9 ' sheets of steel and need them cut FAST ( time is money), you need to be able to program for speed and accuracy.
The hole in post #22 shows there probably is a problem in the software( the rest of the circle looks ok... ) but if it's not 'mission critical', not a big deal BUT it can be seen.
Well, I do not agree.
If you drive them with waveforms matching the magnetics you can move them with almost infinite resolution, the same as servodrives. Imperfections of the magnetics will of course limit the accuracy and of course you cannot control position because of unknown external forces. If you want to improve further on that there is nobody stopping you from using them in a servo feedback loop with encoders or resolvers as position sensors. So the type of motor has norhing to do with resolution or accuracy.
I am working on a project with steppers at the moment. They have a beautifully sinusoidal back-emf so with sinusoidal currents you get nice smooth motion in between the steps. Since the forces in the application of a plasma cutter are pretty limited and constant I can assure you I can achieve a circle motion with an order of magnitude better accuracy than the roughness of the plasma cut.
If you drive them with waveforms matching the magnetics you can move them with almost infinite resolution, the same as servodrives. Imperfections of the magnetics will of course limit the accuracy and of course you cannot control position because of unknown external forces. If you want to improve further on that there is nobody stopping you from using them in a servo feedback loop with encoders or resolvers as position sensors. So the type of motor has norhing to do with resolution or accuracy.
I am working on a project with steppers at the moment. They have a beautifully sinusoidal back-emf so with sinusoidal currents you get nice smooth motion in between the steps. Since the forces in the application of a plasma cutter are pretty limited and constant I can assure you I can achieve a circle motion with an order of magnitude better accuracy than the roughness of the plasma cut.
I built my plasma table with servos and zero backlash gearboxes that are tuned for max acceleration. Still get wonky holes under 1/4 inch in thin stock. By the time you pierce, back off to cut height, and get the mass moving for a cut there's some deformation. Then half the cut breaks out into the feed in ramp only cutting one side. Also things flex with high acceleration required for thin materials and the gantry mass.
My CNC router I built using steppers with feedback and a Masso controller. They're not perfect either because of torque drop-off above the sweet spot rpm but routing is basically slow. Plasma cutting requires a wide range of speed (from about 5 to 1000 inches per minute) and steppers need to be big to handle it with a rigid gantry over 50 pounds. Also steppers with feedback do have step error built in so things keep moving even with step errors set by you. Where servo drives and encoders don't miss a count spinning at high rpms. Both work the same in the end if properly sized. Only difference is the cost and gearing. If you want perfect holes and no cleanup go fiber laser and they are almost affordable now.
My CNC router I built using steppers with feedback and a Masso controller. They're not perfect either because of torque drop-off above the sweet spot rpm but routing is basically slow. Plasma cutting requires a wide range of speed (from about 5 to 1000 inches per minute) and steppers need to be big to handle it with a rigid gantry over 50 pounds. Also steppers with feedback do have step error built in so things keep moving even with step errors set by you. Where servo drives and encoders don't miss a count spinning at high rpms. Both work the same in the end if properly sized. Only difference is the cost and gearing. If you want perfect holes and no cleanup go fiber laser and they are almost affordable now.
GreensvilleJay
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BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
I've always used US Digital encoders for feedback, far superior to the HP ones I used long ,long ago. Also don't buy off the shelf controllers as none would fill the specs the client wants. Tried to use 'steppers' but even using high voltage power supplies, performance was lacking. Went back to drawing board, revamped a constant current mode air solenoid valve design. Instantly got x10 performance increase. Software is cut in DELPHI,so any PC, anywhere can run it, NOT OS dependent.
Runs With Scissors
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Here are the pics of my set up. If I forgot something just let me know and I can measure it up for you.
Hello,
great, that is perfect ! Thank you very much !
And with water and everything. I like the guide rails, nifty design.
I am wondering now where I could make space in the workshop
I think the shape distortion for smaller holes is the simple fact that the metal is hot already when it comes around finishing the hole and not the motion with the motors. If you cannot modify the motion, modify the shape. Measure a hole and compensate. All you need is a few egg shapes for the smaller holes and then it is cut and paste for perfect round holes.
Kind regards,
Hugo
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