Buying a dusty second-hand Delta. What to do first? June 18, 2019 03:13PM |
Admin Registered: 11 years ago Posts: 3,096 |
Re: Buying a dusty second-hand Delta. What to do first? June 19, 2019 03:42PM |
Registered: 10 years ago Posts: 732 |
Re: Buying a dusty second-hand Delta. What to do first? June 19, 2019 04:05PM |
Admin Registered: 11 years ago Posts: 3,096 |
Quote
hercek
Looks like some Kossel version with RAMPS electronics. Diagonal arms seem too long. Belts too long as well. It will have serious ringing with high accelerations (1 G or more).
Make sure there is no play in it and that the frame is sturdy. Calibrate it numerically e.g. using these: It will work well enough after callibration at about 120 mm/s (definitely if you get rid of the LCD and set segments per second to about 80).
Or get duet electronics for it and ask dc4. You will get numerical calibration directly in the firmware. It makes things easier.
Re: Buying a dusty second-hand Delta. What to do first? June 19, 2019 05:17PM |
Registered: 10 years ago Posts: 732 |
Rule of thumb is that a diagonal rod should have angle of 20° or slightly more when the hotend is most far away from a tower. Don't bother with it. It is not a big deal. Consequences of longer arms are:Quote
Ohmarinus
Is there some kind of fixed length that the diagonal arms need to have?
Yes, if you want to print with high accelerations. If you want to print with 4000 mm/s² as most delta printer users do then don't bother with it. First make some prints with the printer as it is. Later, if you will mind the ringing at the accelerations you want to use then start to think about what to do with the belts.Quote
Ohmarinus
And are those belts really too long?
I use Repetier for ... posslibly last 3 years???Quote
Ohmarinus
About the firmware, is it correct that understand from your reaction that the RepetierFW is better to use on a Delta than Marlin?
Re: Buying a dusty second-hand Delta. What to do first? June 20, 2019 04:36AM |
Admin Registered: 11 years ago Posts: 3,096 |
Quote
hercek
Rule of thumb is that a diagonal rod should have angle of 20° or slightly more when the hotend is most far away from a tower. Don't bother with it. It is not a big deal. Consequences of longer arms are:Quote
Ohmarinus
Is there some kind of fixed length that the diagonal arms need to have?
- numerical calibration will be slightly less stable (it will have harder time to converge to the proper result)
- waste of printing height
- even badly calibrated printer will put the first layer better
Yes, if you want to print with high accelerations. If you want to print with 4000 mm/s² as most delta printer users do then don't bother with it. First make some prints with the printer as it is. Later, if you will mind the ringing at the accelerations you want to use then start to think about what to do with the belts.Quote
Ohmarinus
And are those belts really too long?
I use Repetier for ... posslibly last 3 years???Quote
Ohmarinus
About the firmware, is it correct that understand from your reaction that the RepetierFW is better to use on a Delta than Marlin?
I switched from Marlin to Repetier since Repetier was quicker for small printers (i.e. printers with all dimensions smaller than 65535 microsteps). Maybe Marlin is better now but I did not try it for many years. Maybe Repetier is still quicker even now.
I do not have enough experience with 32 bit boards to give any reasonable opinion except:
- 32 bit boards are quicker and you will not need to be so careful about configuration which does not waste MCU cycles.
- Some 32 bit board support numerical calibration directly in the firmware (at least duet + reprap fw).
Re: Buying a dusty second-hand Delta. What to do first? June 20, 2019 04:46AM |
Registered: 10 years ago Posts: 732 |
Re: Buying a dusty second-hand Delta. What to do first? June 20, 2019 08:03AM |
Registered: 10 years ago Posts: 14,672 |
Quote
Ohmarinus
The Duet is not in my budget sadly. Combined with TMC2208 or TMC2130 drivers I'll be able to make it livingroom suitable. I'll have to check which I like more, UART vs SPI and what the Amps are.
Re: Buying a dusty second-hand Delta. What to do first? June 21, 2019 12:44PM |
Registered: 7 years ago Posts: 619 |
Quote
hercek
Rule of thumb is that a diagonal rod should have angle of 20° or slightly more when the hotend is most far away from a tower. Don't bother with it. It is not a big deal. Consequences of longer arms are:Quote
Ohmarinus
Is there some kind of fixed length that the diagonal arms need to have?
- numerical calibration will be slightly less stable (it will have harder time to converge to the proper result)
- waste of printing height
- even badly calibrated printer will put the first layer better
Yes, if you want to print with high accelerations. If you want to print with 4000 mm/s² as most delta printer users do then don't bother with it. First make some prints with the printer as it is. Later, if you will mind the ringing at the accelerations you want to use then start to think about what to do with the belts.Quote
Ohmarinus
And are those belts really too long?
I use Repetier for ... posslibly last 3 years???Quote
Ohmarinus
About the firmware, is it correct that understand from your reaction that the RepetierFW is better to use on a Delta than Marlin?
I switched from Marlin to Repetier since Repetier was quicker for small printers (i.e. printers with all dimensions smaller than 65535 microsteps). Maybe Marlin is better now but I did not try it for many years. Maybe Repetier is still quicker even now.
I do not have enough experience with 32 bit boards to give any reasonable opinion except:
- 32 bit boards are quicker and you will not need to be so careful about configuration which does not waste MCU cycles.
- Some 32 bit board support numerical calibration directly in the firmware (at least duet + reprap fw).
Re: Buying a dusty second-hand Delta. What to do first? June 21, 2019 07:46PM |
Admin Registered: 11 years ago Posts: 3,096 |
Re: Buying a dusty second-hand Delta. What to do first? June 23, 2019 01:52PM |
Registered: 10 years ago Posts: 732 |
Re: Buying a dusty second-hand Delta. What to do first? June 24, 2019 12:51PM |
Registered: 7 years ago Posts: 619 |
"It is good when planes containing diagonal rods of one tower contain the hotend tip because the intersection point of these 3 planes defines the point around which hotend rotates when there is play in ball joints. That position minimizes the errors. But notice that the position of the point of the rotation relative to the effector changes with XY position. Therefore you cannot place it perfectly."Quote
hercek
@ldc60:
20° between diagonal rod and the heat bed when the effector is furthest from the corresponding tower.
Only these rules come to my mind when deciding effector (platform) radius:
- The bigger it is the more horizontal space is wasted.
- Bigger platform allows bigger diagonal rod separation which minimizes bad consequences of the errors in diagonal rod length and ball joint positions. Put diagonal rods corresponding to one tower as far away as your platform allows.
- It is good when planes containing diagonal rods of one tower contain the hotend tip because the intersection point of these 3 planes defines the point around which hotend rotates when there is play in ball joints. That position minimizes the errors. But notice that the position of the point of the rotation relative to the effector changes with XY position. Therefore you cannot place it perfectly.
Re: Buying a dusty second-hand Delta. What to do first? June 24, 2019 04:31PM |
Registered: 10 years ago Posts: 732 |
Re: Buying a dusty second-hand Delta. What to do first? November 14, 2019 06:42PM |
Admin Registered: 11 years ago Posts: 3,096 |
Re: Buying a dusty second-hand Delta. What to do first? November 16, 2019 09:21AM |
Admin Registered: 11 years ago Posts: 3,096 |