LISA Simpson
Posted by nicholas.seward
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Re: LISA Simpson January 26, 2014 09:56PM |
My base has morphed a bit:
It still fits through the ever famous door. It's optimized for motors and electronics above the mid plate. More or less - no more bottom plate.
It still fits through the ever famous door. It's optimized for motors and electronics above the mid plate. More or less - no more bottom plate.
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Re: LISA Simpson February 06, 2014 09:58PM |
Any comments on this fork design?
If you look at the second photo
you can see my particular design with the corner structure causes interference with the current configuration. Correct me if I'm wrong ,but this shouldn't change any of the geometry using the fork design.
If you look at the second photo
you can see my particular design with the corner structure causes interference with the current configuration. Correct me if I'm wrong ,but this shouldn't change any of the geometry using the fork design.
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Re: LISA Simpson February 07, 2014 05:20AM |
Quote
Dannydefe
Correct me if I'm wrong ,but this shouldn't change any of the geometry using the fork design.
Double shear joint reduces error:
There is the potential to print a more accurate part, and reduce the error with Lisa if you use an inline double shear arms (i.e. eliminate offset-shoulder),
I believe it will save you 12,000 CPU cycles, (4000 cycle hit per motor x 3 motors = 12,000 CPU cycles).
Pickle fork saves CPU cycles:
Using a pickle fork to constrain the nut from rotating eliminates the g-code preprocessor, and I think will speed things up as well.
To prevent the nut from rotating, substitute a rigid metal column for the PVC column.
Fabricate a bracket to carry 2 bearings to ride up and down the metal column.
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uncle_bob
“Since the main impact is from the tan function,”
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Hazer
“For LISA, the shoulders and the hub offset stays in line with the arm in the X-Y coordinates.
They can no longer be ignored like the Rostock does. By throwing them back into the equations,
you would need to perform two more squares and one more square-root per motor.
With the threaded rod offset, you would also need to add one SIN/COS equation to compensate the movement of the thread.
That unfortunately is a 4000 cycle hit per motor.
So, Marlin Rostock would be 3120 processor cycles per move at 16MHz would take 195 usec.
Adding LISA calculations to firmware would change to 18480 cycles, or 1.1 milliseconds.
I have no idea what impact that could have.”
Edited 2 time(s). Last edit at 02/07/2014 05:22AM by A2.
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Re: LISA Simpson February 07, 2014 11:46AM |
All my joints have been one-sided to allow poorly tuned printers to work for as many parts as possible. It also reduces assembly time.
Fork joints are superior. (Assuming that the fins of the forks are thick enough.) I have been considering going that direction. It has a nice side benefit of making the longest part only 125mm (from the model below) for a printer that has a 225mm print diameter. That means you can make a 1.8X LISA on a forked LISA. (If optimization of the macrocreation factor is desired you can even do better than that. I came up with 2.2X with just a little playing around.)
Here is how I would do it. I only uses 1 more unique plastic part than my previous design. You do need 12 M3x35 SHCS and matching nuts. That seems like a small price.
I am also considering doing this for GUS so that the motor/slave arms will be printable on a 150x100 printer.
ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ
Fork joints are superior. (Assuming that the fins of the forks are thick enough.) I have been considering going that direction. It has a nice side benefit of making the longest part only 125mm (from the model below) for a printer that has a 225mm print diameter. That means you can make a 1.8X LISA on a forked LISA. (If optimization of the macrocreation factor is desired you can even do better than that. I came up with 2.2X with just a little playing around.)
Here is how I would do it. I only uses 1 more unique plastic part than my previous design. You do need 12 M3x35 SHCS and matching nuts. That seems like a small price.
I am also considering doing this for GUS so that the motor/slave arms will be printable on a 150x100 printer.
ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ
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Re: LISA Simpson February 07, 2014 06:42PM |
Quote
nicholas.seward
Fork joints are superior. (Assuming that the fins of the forks are thick enough.) I have been considering going that direction. It has a nice side benefit of making the longest part only 125mm (from the model below) for a printer that has a 225mm print diameter. That means you can make a 1.8X LISA on a forked LISA. (If optimization of the macrocreation factor is desired you can even do better than that. I came up with 2.2X with just a little playing around.)
Pretty cool you can shorten the main part of the arm, that allows the smaller printers to replicate a bigger printer, i.e. Lisa.
And by increasing the length of the double shear joint, you can further increase the overall length
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Re: LISA Simpson February 09, 2014 01:16PM |
If each of the shoulder joints connected to a motor and propeller, you would have a flying printer with motion controlled by the relative RPMs of each motor? 
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Re: LISA Simpson February 18, 2014 09:15PM |
Here is something I've been playing around with. The forked arms are contained with MR6702-ZZ (15 x 21 x 4 mm) Ball Bearing which will mate with a solid aluminum plug on either the shoulder or the hub fixtures. I'm still playing around with the configuration for the aluminum plug, I'm not sure if the first photo with shoulders step for the Bearings race might perform better than just straight aluminum plug which is press-fit into the shoulder. My goal is reduced weight, zero play and to reduce the width of the shoulder joint so that it doesn't interfere with my carbon corner supports.
aluminum plug
New fork arm
aluminum plug
New fork arm
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