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DXU - Efficient Dual Extrusion Upgrade for UM2+

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+
16 hours ago, garaha2012 said:

Hi, everyone,

congratulation for the great work yyh1002, very impressive!

l do have a question:

The hot end unit that moves up and down surely has some play in it otherwise it would not move up and down.

When the hot end is in the down position how is the unit held in its precise x-y-location?
On my UM3 the precision comes from the spring pressing the moving hot end unit down against a tapered seat in a metal part at the bottom of the head.
Which part or which lay-out in your design ensures the x-y-position precisely?

Or do I expect problems where there is none??

Thanks and sorry to ask this after everyone says it prints fine.

 

Thanks. Good observation. On the front housing, there are two bores to restrain the hotend for xy precision, one is above the heatsink and spring, the other is around the bowden coupler. Both bores have teeth around them so it's easier for the hotend to slide. I made the tolerance quite tight and use a drill to spin the hotend inside the housing to run-in. It's metal vs plastic so they fit quite well without being all fixed.

 

I agree that it's not as precise as UM3's tapered socket solution, technically. But I think it's good enough for 3D printing purpose if fitted well, just like the brass bushing on XY rails. I would like to go with more precise solution if I have easy access to machines. 

 

9 hours ago, luke199 said:

Hey guys,

 

just to confirm the PI insulator goes between the nozzle and boden tube? has anyone had any problems with leaks or disassembly where the boden meets the insulator?

 

The PI insulator does go between the nozzle and bowden tube. The bowden tube coming with hotend is intended to be used without PI insulator, so it needs to be trimmed slightly shorter. But the total length of tube+PI should be slightly longer (about 0.5mm) than the shaft to keep the bowden tube in compression so it doesn't get squeezed shorter by hot filament over time.

 

You need to make sure the nozzle is right up against the heat break, metal to metal. Heat the block to at least 160 degrees before install. And hold the block firmly when screw nozzle in. If there is cold plastic, debris or air gap between the nozzle and heat break, it will leak. 

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+
On 10/10/2019 at 3:03 AM, yyh1002 said:

 

Thanks. Good observation. On the front housing, there are two bores to restrain the hotend for xy precision, one is above the heatsink and spring, the other is around the bowden coupler. Both bores have teeth around them so it's easier for the hotend to slide. I made the tolerance quite tight and use a drill to spin the hotend inside the housing to run-in. It's metal vs plastic so they fit quite well without being all fixed.

 

I agree that it's not as precise as UM3's tapered socket solution, technically. But I think it's good enough for 3D printing purpose if fitted well, just like the brass bushing on XY rails. I would like to go with more precise solution if I have easy access to machines. 

 

 

The PI insulator does go between the nozzle and bowden tube. The bowden tube coming with hotend is intended to be used without PI insulator, so it needs to be trimmed slightly shorter. But the total length of tube+PI should be slightly longer (about 0.5mm) than the shaft to keep the bowden tube in compression so it doesn't get squeezed shorter by hot filament over time.

 

You need to make sure the nozzle is right up against the heat break, metal to metal. Heat the block to at least 160 degrees before install. And hold the block firmly when screw nozzle in. If there is cold plastic, debris or air gap between the nozzle and heat break, it will leak. 

 

Thank you, just to make sure it's clear.  I do the follow.

 

1 place the PI insulator into the heatsink and screw tight into the heater block

2 screw nozzle in afterwords.

 

and this would mean the nozzle will stick out the heater block a little more.

 

 

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+
2 hours ago, luke199 said:

place the PI insulator into the heatsink and screw tight into the heater block

Not really. There needs to be about 1-2mm spacing between the top of heat block and hex flange on heat break. The block is loose before install the nozzle, and you can turn it to proper direction so it doesn't touch anything. When nozzle comes in, it will lock everything tight. 

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+

There is a printer definition in the latest Cura for Mark2 variant, has anyone edited to create a DXU profile in Cura 4.3?

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+

Hey all,

 

What's the recommended general retraction length and maximum?

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+

The DXU works with Cura 4.03 if choosing the Mark2, input your printer specific dimensions and filament, even the post processing file works, change the start- Goode to match the DXU profile we have in Cura 3.6 and that’s it..so far I have printed calibration cubes with dual color with no issues, have not printed a large model yet.  Think it is promising 

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+

DXU and Cura 4.3 - changed the disallowed areas to match the DXU def.json file and the backplate image. Print area is now showing as the original DXU - without it the print area is minimal on the Mark2 def.json if choosing extruder 1 and 2

does anybody knows if other changes are needed?

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+
1 hour ago, Garufa said:

DXU and Cura 4.3 - changed the disallowed areas to match the DXU def.json file and the backplate image. Print area is now showing as the original DXU - without it the print area is minimal on the Mark2 def.json if choosing extruder 1 and 2

does anybody knows if other changes are needed?

I haven't checked the new embedded Mark2 profile. You will also need to change platform shift and print area. I'm not sure if Mark2 has the material adhesion option enabled.

But for me the old DXU profile works directly with Cure 4.3, so I didn't find it necessary to do a new version. Did it not work for you?

 

On 10/29/2019 at 2:36 AM, luke199 said:

Hey all,

 

What's the recommended general retraction length and maximum?

I use 6.5mm, 25mm/s, same as UM2+ default.

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+

yyh1002, My bad, when migrating to version 4.0 all my settings became corrupted and could not make it work. I just tried with 4.3 again with your profile and works !!! - thank you.

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Posted · DXU - Efficient Dual Extrusion Upgrade for UM2+

Thanks yyh1002.  I run some tests and between 2.70 and 3.50 @25mm/s is perfect depending on material

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