Dual X MakerSlide with room in between?

discussion of design changes / improvements / suggestions
wlanfox
Posts: 74
Joined: Sat Oct 20, 2012 10:49 am

Re: Dual X MakerSlide with room in between?

Post by wlanfox » Mon Jan 21, 2013 11:07 am

This is actually a great IDEA if a second Z axis rail is put in place, this way the forces pushing back on the spindle will be equal on both rails. I also added a gantry to my set up, but still there is an annoying deflection when a WIDE tool penetrates the material, this is a good 0.5mm. Due to the spindle only been secure by one side of it. I been studying this defection with different bits wide and thin; as mention is a lot more evident with wide drill bits say 4mm, using a end-mill is better since the end-mill has a better penetration cutting sufferance then a regular drill bit. This deflection seem to be mostly observe in the v-wheels both the Z-axis and X-axis the two of them added ends in the 0.5mm issue when dealing with wide bits also depends on the material harder material worse of-course.

So I am thinking that if I widen my double gantry and actually put the spindle in the middle as shown here. But instead of having only one Z-axis rail, also have two, the stepper only needs to drive one side but the second rail will add support to avoid any rotatory deflection on the Z-axis.

This is an example of what happens, in the picture before penetration the bit was dead center. As it started to touche the surface it started pushing back and since this basically makes a circle where the spindle is the radius, and gantry is the center of the circle, as you push the bits moves out in the negative Y-direction. Until it penetrates but at that point is too late. Yes I have lower the feed rate down to 20mm/m for this operation.

Left board, 20mm/min feed rate, Right side , stopped the machine and lower it 0.1mm at the time holding the spindle, making sure I didn't push to hard and cause it to have the same problem on the opposite direction.

Image

What do you guys think, any reasons why this arrangement whit double Z-axis rails will not help fix this issue??

T4b
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Re: Dual X MakerSlide with room in between?

Post by T4b » Mon Jan 21, 2013 3:34 pm

wlanfox wrote:So I am thinking that if I widen my double gantry and actually put the spindle in the middle as shown here. But instead of having only one Z-axis rail, also have two, the stepper only needs to drive one side but the second rail will add support to avoid any rotatory deflection on the Z-axis.
I thought about that.
  • It would be a pain to change the tool
  • I'm not sure how much it would help unless you drive both sides
  • It would add quite some additional complexity
I think probably increasing the distance between the upper and lower v-wheels on the z-axis would help more, as would replacing the delrin v-wheels with steel ones.
ShapeOko #658
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