Hello everyone,
I have just built my corexy machine and found the scale of X, Y has some problem. Searching a lot and still cannot find a piece of information for turning the machine. After studying the equation again and again, doing a lot of trial and error, resulting my steps to tunning my corexy machine and could like have a share (Sorry for my poor English, it isn't my first language). Please correct me it anything I made wrong.
![reference.png]( "reference.png")
Looked back to the corexy.com's reference, it made a hint of turning the machine. Let's do some maths first.
Why I need do such maths?
The reason is we have ΔA and ΔB: When we tune ΔA, we need zeroized the effect on ΔB and the reverse is same.
Therefore:-
ΔX = 1/2(ΔA+ΔB ) , ΔY = 1/2(ΔA - ΔB )
1. ΔA=20mm , ΔＢ= 0mm
![a_move.png]( "a_move.png")
2. ΔA = 0mm , ΔＢ= 20mm
![b_move.png]( "b_move.png")
Concluded from 1 and 2, we can find that if we only move ΔA, the direction will be 45 degrees forward and if move ΔB the direction will be -45 degrees forward.
This is the theory behind my tuning steps.
To tunning the X, Y axis, there involves 3 steps and 2 sections to tuning.
The 2 section for tuning are
1. The elastic of ΔA and ΔB's belt
2. The Steps per unit of X, Y in the firmware
Steps to tune
1. Test Cube printing
Before we can tune, we need to know the current printing result. To know the current print result, we can print a cube.
I am using this one download from Thingiverse:
[www.thingiverse.com]
![10mmcube.png]( "10mmcube.png")
Remember, we need rotate the cube to 45 degrees when print it.
![45.png]( "45.png")
When the printing completed, we should measure the red and yellow side marked at below picture
![45_1.png]( "45_1.png")
2. Fine tune the scale of X and Y
If the scale perfect, ΔA(Red) and ΔB(Yellow) should be in same mm. if not, we need to adjust the loose or tight to the belts.
if ΔA > ΔB, it means the belt of ΔA is much tightened than the belt of ΔB, so we made the belt of ΔB more tight or made the belt of ΔA a bit loose.
if ΔA < ΔB, just do it in opposite.
Repeat these two steps until the result is acceptable, for me, means the different less than 0.05mm.
3. Calculate fine tuned step per unit
When the scale is corrected, we can start tuned step per unit, It just same as an other Cartesian machine.
The difference is we just need measure 1 side (In theory, X and Y's value of step per unit should be the same).
e.g. Model 10mm, print out 11mm
new value = 10/11 * 80 (normal GT2 belt + 20theeth + A4988) = 72.23
Input GCode: M92 X72.23 Y72.23
Print the cube again to get the result, and repeat steps until the result is satisfied.
I have just built my corexy machine and found the scale of X, Y has some problem. Searching a lot and still cannot find a piece of information for turning the machine. After studying the equation again and again, doing a lot of trial and error, resulting my steps to tunning my corexy machine and could like have a share (Sorry for my poor English, it isn't my first language). Please correct me it anything I made wrong.
Looked back to the corexy.com's reference, it made a hint of turning the machine. Let's do some maths first.
Why I need do such maths?
The reason is we have ΔA and ΔB: When we tune ΔA, we need zeroized the effect on ΔB and the reverse is same.
Therefore:-
ΔX = 1/2(ΔA+ΔB ) , ΔY = 1/2(ΔA - ΔB )
1. ΔA=20mm , ΔＢ= 0mm
2. ΔA = 0mm , ΔＢ= 20mm
Concluded from 1 and 2, we can find that if we only move ΔA, the direction will be 45 degrees forward and if move ΔB the direction will be -45 degrees forward.
This is the theory behind my tuning steps.
To tunning the X, Y axis, there involves 3 steps and 2 sections to tuning.
The 2 section for tuning are
1. The elastic of ΔA and ΔB's belt
2. The Steps per unit of X, Y in the firmware
Steps to tune
1. Test Cube printing
Before we can tune, we need to know the current printing result. To know the current print result, we can print a cube.
I am using this one download from Thingiverse:
[www.thingiverse.com]
Remember, we need rotate the cube to 45 degrees when print it.
When the printing completed, we should measure the red and yellow side marked at below picture
2. Fine tune the scale of X and Y
If the scale perfect, ΔA(Red) and ΔB(Yellow) should be in same mm. if not, we need to adjust the loose or tight to the belts.
if ΔA > ΔB, it means the belt of ΔA is much tightened than the belt of ΔB, so we made the belt of ΔB more tight or made the belt of ΔA a bit loose.
if ΔA < ΔB, just do it in opposite.
Repeat these two steps until the result is acceptable, for me, means the different less than 0.05mm.
3. Calculate fine tuned step per unit
When the scale is corrected, we can start tuned step per unit, It just same as an other Cartesian machine.
The difference is we just need measure 1 side (In theory, X and Y's value of step per unit should be the same).
e.g. Model 10mm, print out 11mm
new value = 10/11 * 80 (normal GT2 belt + 20theeth + A4988) = 72.23
Input GCode: M92 X72.23 Y72.23
Print the cube again to get the result, and repeat steps until the result is satisfied.
