Problems that popped up building a Prusa
Posted by sgall
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Problems that popped up building a Prusa April 01, 2012 05:25AM |
Registered: 12 years ago Posts: 4 |
This post is intended for people, like myself, who may not familiar with a number of technical things when building a Prusa.
The post is in the form a fairly freeform list. I intend to more structured notes later.
Mistakes I made during the build of the frame:
1. Y axis motor bracket round the wrong way.
The base of the plastic should be parallel to the table below.
I put it round the other because the motor seemed to fit better the other way. This was due extra thick plastic on the motor attachment.
I had to cut the extra plastic off to get my motors to fit.
2. Extruder assembly round wrong way.
The belt should be at the back, and the extruder motor at front.
3. X and Y pulleys slipped.
I filed flats on the shaft. This was not enough because the M3 nut turned in its slot. I packed the slot with kneadbable epoxy putty and set the nut in this.
So far this seems to work.
4. Y axis rods dont seem very secure.
The Y axis rods can protruded beyond the X motor assembly but can slip out. They seemed to fixed on the idler end with a M3 bolt. I consider this insecure and I would like
a better way to fix. I havent thought of one yet, keeping in mind that if the rods become too rigidly fixed they may be subject to jamming.
5. Mechanical end stop switches.
I am yet to calibrate my machine. I am unclear where the switches should go and what part of the movable axis structures they should strike against.
The post is in the form a fairly freeform list. I intend to more structured notes later.
Mistakes I made during the build of the frame:
1. Y axis motor bracket round the wrong way.
The base of the plastic should be parallel to the table below.
I put it round the other because the motor seemed to fit better the other way. This was due extra thick plastic on the motor attachment.
I had to cut the extra plastic off to get my motors to fit.
2. Extruder assembly round wrong way.
The belt should be at the back, and the extruder motor at front.
3. X and Y pulleys slipped.
I filed flats on the shaft. This was not enough because the M3 nut turned in its slot. I packed the slot with kneadbable epoxy putty and set the nut in this.
So far this seems to work.
4. Y axis rods dont seem very secure.
The Y axis rods can protruded beyond the X motor assembly but can slip out. They seemed to fixed on the idler end with a M3 bolt. I consider this insecure and I would like
a better way to fix. I havent thought of one yet, keeping in mind that if the rods become too rigidly fixed they may be subject to jamming.
5. Mechanical end stop switches.
I am yet to calibrate my machine. I am unclear where the switches should go and what part of the movable axis structures they should strike against.
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Re: Problems that popped up building a Prusa April 01, 2012 06:24PM |
Registered: 13 years ago Posts: 241 |
sgall Wrote:
-------------------------------------------------------
> This post is intended for people, like myself, who
> may not familiar with a number of technical things
> when building a Prusa.
>
> The post is in the form a fairly freeform list. I
> intend to more structured notes later.
>
> Mistakes I made during the build of the frame:
>
> 1. Y axis motor bracket round the wrong way.
> The base of the plastic should be parallel to the
> table below.
> I put it round the other because the motor seemed
> to fit better the other way. This was due extra
> thick plastic on the motor attachment.
> I had to cut the extra plastic off to get my
> motors to fit.
Easy mistake to make...
> 2. Extruder assembly round wrong way.
> The belt should be at the back, and the extruder
> motor at front.
It don't really matter, I have had my extrduder both ways.
> 3. X and Y pulleys slipped.
> I filed flats on the shaft. This was not enough
> because the M3 nut turned in its slot. I packed
> the slot with kneadbable epoxy putty and set the
> nut in this.
> So far this seems to work.
I changed the printed pullies to Alum ones from ebay, by doing this improves the prints and made my holes round.
[www.ebay.com]
> 4. Y axis rods dont seem very secure.
> The Y axis rods can protruded beyond the X motor
> assembly but can slip out. They seemed to fixed on
> the idler end with a M3 bolt. I consider this
> insecure and I would like
> a better way to fix. I havent thought of one yet,
> keeping in mind that if the rods become too
> rigidly fixed they may be subject to jamming.
I think you may have your axis around the wrong way when I read this..
The X axis is fr your extruder carriage, the rods go into the X motor and idler with could have 4 M3 bolt holes, you add the nut on the inside and insert the bolt from the out side, insert the rod and tighten the bolt as to tap the rod.
The Y axis rods are held in place ny the y clamps that are held tight on the all theard and unts.
> 5. Mechanical end stop switches.
> I am yet to calibrate my machine. I am unclear
> where the switches should go and what part of the
> movable axis structures they should strike
> against.
You only need 3 end stops, X axis, Y axis and Z axis, all 3 should be set to the MIN of each travel. By doing this when we home we move to the stating point 0,0,0.
OK, with that said.
With the you sitting in front of the print, and the belt for the X axis behind the extruder we have set the front of the printer.
The X axis end stop goes to your left and attaches to the front rod and it uses yhe side of the carraige to stop the motor
The Y axis end stop goes to the back on the print and attaches to the all theard and is stoped by the Y carriage
The Z axis end stop gpes to the left and attaches to the Z rod so the end stop is under the X holder.
You don't need a MAX end stop as the travel is set in the firmware.
Hope that helps
Auzze
-------------------------------------------------------
> This post is intended for people, like myself, who
> may not familiar with a number of technical things
> when building a Prusa.
>
> The post is in the form a fairly freeform list. I
> intend to more structured notes later.
>
> Mistakes I made during the build of the frame:
>
> 1. Y axis motor bracket round the wrong way.
> The base of the plastic should be parallel to the
> table below.
> I put it round the other because the motor seemed
> to fit better the other way. This was due extra
> thick plastic on the motor attachment.
> I had to cut the extra plastic off to get my
> motors to fit.
Easy mistake to make...
> 2. Extruder assembly round wrong way.
> The belt should be at the back, and the extruder
> motor at front.
It don't really matter, I have had my extrduder both ways.
> 3. X and Y pulleys slipped.
> I filed flats on the shaft. This was not enough
> because the M3 nut turned in its slot. I packed
> the slot with kneadbable epoxy putty and set the
> nut in this.
> So far this seems to work.
I changed the printed pullies to Alum ones from ebay, by doing this improves the prints and made my holes round.
[www.ebay.com]
> 4. Y axis rods dont seem very secure.
> The Y axis rods can protruded beyond the X motor
> assembly but can slip out. They seemed to fixed on
> the idler end with a M3 bolt. I consider this
> insecure and I would like
> a better way to fix. I havent thought of one yet,
> keeping in mind that if the rods become too
> rigidly fixed they may be subject to jamming.
I think you may have your axis around the wrong way when I read this..
The X axis is fr your extruder carriage, the rods go into the X motor and idler with could have 4 M3 bolt holes, you add the nut on the inside and insert the bolt from the out side, insert the rod and tighten the bolt as to tap the rod.
The Y axis rods are held in place ny the y clamps that are held tight on the all theard and unts.
> 5. Mechanical end stop switches.
> I am yet to calibrate my machine. I am unclear
> where the switches should go and what part of the
> movable axis structures they should strike
> against.
You only need 3 end stops, X axis, Y axis and Z axis, all 3 should be set to the MIN of each travel. By doing this when we home we move to the stating point 0,0,0.
OK, with that said.
With the you sitting in front of the print, and the belt for the X axis behind the extruder we have set the front of the printer.
The X axis end stop goes to your left and attaches to the front rod and it uses yhe side of the carraige to stop the motor
The Y axis end stop goes to the back on the print and attaches to the all theard and is stoped by the Y carriage
The Z axis end stop gpes to the left and attaches to the Z rod so the end stop is under the X holder.
You don't need a MAX end stop as the travel is set in the firmware.
Hope that helps
Auzze
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