New CoreXYU build. Need advice on bed leveling.. March 13, 2019 06:26AM |
Registered: 5 years ago Posts: 6 |
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 08:30AM |
Registered: 5 years ago Posts: 25 |
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 08:45AM |
Registered: 5 years ago Posts: 148 |
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 09:19AM |
Registered: 5 years ago Posts: 6 |
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Ernest1122
with a 160c chamber you got about 140c temp difference inside and outside but didn't see how you deal with the thermal expansion?
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Pippy
Are drive belts OK to work in those conditions as well I wonder ?
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 10:57AM |
Registered: 11 years ago Posts: 5,780 |
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 11:00AM |
Registered: 11 years ago Posts: 5,780 |
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 01:00PM |
Registered: 5 years ago Posts: 148 |
Re: New CoreXYU build. Need advice on bed leveling.. March 13, 2019 01:54PM |
Registered: 10 years ago Posts: 14,672 |
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floesi
1. (Heat resistant) Proximity sensor + True bed leveling (with 3 steppers+leadscrews)
It is supported by DuetWifi, but does this actually bring that much of an advantage? Is stepper synchronization a big factor? Cost is not that big of a factor in my case.
2. (Heat resistant) Proximity sensor + Z compensation (1 stepper, 3 leadscrews)
Let’s say I print a cube: When compensating over the first x layers, the bottom and top layers aren’t parallel right? When compensating during the whole print, do I end up with a parallelogram or are the vertical walls printed perpendicular to the bed? (I know, exaggerated of course)
3. No bed leveling, table screws (1 stepper, 3 leadscrews)
Re: New CoreXYU build. Need advice on bed leveling.. March 14, 2019 05:28AM |
Registered: 5 years ago Posts: 6 |
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the_digital_dentist
The bed plate thermal expansion it relatively easy to deal with if you put it on a kinematic mount. The thing you have to look out for is the expansion of the printer's frame which will move the linear guides apart in the Y axis and the guide rails apart in the Z axis. It may be less of a problem in Z because the rails will tend to flex.
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the_digital_dentist
You'll have to water cool the hot-end or bring in outside air with a hose.
Re: New CoreXYU build. Need advice on bed leveling.. March 20, 2019 08:22AM |
Registered: 5 years ago Posts: 6 |
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dc42
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floesi
1. (Heat resistant) Proximity sensor + True bed leveling (with 3 steppers+leadscrews)
It is supported by DuetWifi, but does this actually bring that much of an advantage? Is stepper synchronization a big factor? Cost is not that big of a factor in my case.
2. (Heat resistant) Proximity sensor + Z compensation (1 stepper, 3 leadscrews)
Let’s say I print a cube: When compensating over the first x layers, the bottom and top layers aren’t parallel right? When compensating during the whole print, do I end up with a parallelogram or are the vertical walls printed perpendicular to the bed? (I know, exaggerated of course)
3. No bed leveling, table screws (1 stepper, 3 leadscrews)
Go for either #1 or #3. #1 is electrically more complex (i.e. 2 extra stepper motors + wires). #3 is mechanically more complex (extra belt, belt tension adjustment, thrust bearings, pulleys, levelling screws). Your choice. As you are building an IDEX machine, you already need at least a DueX2 expansion board. The DueX5 (which you will need instead of the DueX2 for the extra Z motors) doesn't cost a lot more, so the additional cost of #3 isn't so much.
Re: New CoreXYU build. Need advice on bed leveling.. March 20, 2019 09:27AM |
Registered: 11 years ago Posts: 5,780 |
Re: New CoreXYU build. Need advice on bed leveling.. March 20, 2019 12:31PM |
Registered: 6 years ago Posts: 1,007 |
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floesi
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dc42
Quote
floesi
1. (Heat resistant) Proximity sensor + True bed leveling (with 3 steppers+leadscrews)
It is supported by DuetWifi, but does this actually bring that much of an advantage? Is stepper synchronization a big factor? Cost is not that big of a factor in my case.
2. (Heat resistant) Proximity sensor + Z compensation (1 stepper, 3 leadscrews)
Let’s say I print a cube: When compensating over the first x layers, the bottom and top layers aren’t parallel right? When compensating during the whole print, do I end up with a parallelogram or are the vertical walls printed perpendicular to the bed? (I know, exaggerated of course)
3. No bed leveling, table screws (1 stepper, 3 leadscrews)
Go for either #1 or #3. #1 is electrically more complex (i.e. 2 extra stepper motors + wires). #3 is mechanically more complex (extra belt, belt tension adjustment, thrust bearings, pulleys, levelling screws). Your choice. As you are building an IDEX machine, you already need at least a DueX2 expansion board. The DueX5 (which you will need instead of the DueX2 for the extra Z motors) doesn't cost a lot more, so the additional cost of #3 isn't so much.
After some pondering and tweaking I decided on #1 true bed leveling.
This brought me to the next question: which Z probe.
First I wanted to use an inductive proximity sensor, but they're huge and heat resistance makes them super expensive, plus they aren't the most accurate option. After a lot of additional reading on the topic I came across piezo electric sensors. Problem is heat again, so I have to keep them outside of the build chamber.
Where would I best place them? Does bed leveling work when theyre so far away from where the nozzle touches the glass (picture below)?
[attachment 110633 8.PNG]
Or are there better options for high temperatures?
Re: New CoreXYU build. Need advice on bed leveling.. March 21, 2019 07:08AM |
Registered: 5 years ago Posts: 6 |
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the_digital_dentist
If you build the machine with a stable platform to support the bed plate and a stable leveling system for the plate itself, you won't need autoleveling and you won't have to manually relevel. 3 lead screws to lift the bed should be stable and will maintain constant position if the screws are all belted to one motor. 3 point kinematic mount on the bed plate will be stable, too. You'll set it level once, manually, and it will stay that way until you take the machine apart.
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MKSA
I think the same as DD, that I summarize as: ABL for a Cartesian 3D printer is a sign of a poor design/make.
Re: New CoreXYU build. Need advice on bed leveling.. March 21, 2019 07:39AM |
Registered: 11 years ago Posts: 5,780 |
Re: New CoreXYU build. Need advice on bed leveling.. March 21, 2019 09:18AM |
Registered: 5 years ago Posts: 6 |
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the_digital_dentist
I wouldn't count on that type of switch to be repeatable.
You can use an opto interruptor at one of the arms that connects to the bed support outside the oven to set Z=0. If the bed plate is 10 mm thick and you raise its temperature 150C the vertical expansion is only about 37 um. It will be consistent, so set the sensor to trigger at Z=0 at room temperature, then in the filament profiles that set the temperature of the bed and hot-end, set a Z=0 offset to compensate for that filament's bed temperature. If you're printing ABS with a bed temperature of 100C, set one Z=0 offset for 100C. If you're printing PEEK with the bed set to 180C, use another Z=0 offset for that.
You may need to look at different adhesives to attach the heater to the bed plate. The 468MP that is commonly used on the Keenovo heaters may not like the maximum bed temperature you intend to use. It might be better to use a mechanical clamp to hold the heater on the bed plate so you don't have to worry about adhesive burning up and letting go.
You can eliminate bed leveling and heating if you print on a sacrificial foam bed...