Remodeling my existing printer for better prints

Hi, I am currently trying to rebuild an existing printer to be more Prusa-like. Ive gotten a few DIY printer sets and understand the basics behind the setup and maintenance, but none of my sets are quite as refined as my Prusa Mini+. What I would like to do is add smooth rods and LM8UU for increased stability, as well as a belt-driven z-axis with dual lead screws. I know I can function on my current electronics (mks and a4988)for a brief time but I would like recommendations on motherboard and drivers that will give quiet operation and quality prints. I understand that the drivers are better in the prusa but I still cannot understand why the prints are so much better. Even though the stepper motors are comparable and the lead screw is the same pitch, there is much less Z wobble and the prusa needs far less maintenance for hot end and nozzles, clogs, etc. I believe that it must be the firmware or the motherboard itself that is giving this advantage. When I read on drivers however, it seems that the only advantage of the Trinamic over the A4988 is noise and power consumption. Can anyone help me understand in a general way what I should be looking for to have a quiet and stable printer? The top of my list so far is the Duet 2 wifi, but I do not like built in drivers if I can avoid them. Is there another board of similar quality/price that offers swappable drivers?

--TL: DR--
I would like a recommendation on motherboard to upgrade my printer. Marlin compatibility is a plus, as well as swappable stepper drivers.

Edited 1 time(s). Last edit at 03/14/2022 07:58AM by Godzilleni.

2 mods that have reduced noise and vibration on my printer;-

1) Replacing smooth return roller pulleys with toothed gears to eliminate belt rub.

2) Adding rubber shock absorbers to the stepper motors.

Measure the belts too. One cheap trick manufacturers do is use quarter inch wide, which have a slightly different pitch to G2 6mm belts.

It's not a huge difference but it does not work as well as using correct belt size.

Driver chips soldered to the board are generally more reliable than those tiny driver modules that can't dissipate heat. It's usually easier and more accurate to set the motor current via the config file than to have to mess around with adjusting tiny, easily broken pots, while guessing at the motor current. Some people think "I want driver modules so they can be replaced easily when/if they fail.", but they're more likely to fail because they're little modules. What you really want is drivers that don't fail. If you buy a controller that uses driver modules, be sure to buy a handful of extras- you're going to need them. Most of the better controller boards have drivers soldered to the controller board and use the trinamic drivers that can reduce noise level through 256:1 ustepping. The Duet boards are very good.

Rubber motor mounts can help reduce vibrations coupled to the printer's frame and resulting acoustic noise, but they also allow the belt tension to tilt the motor/shaft which affects the way the belt rides on the pulleys. Every time the motor reverses direction it tilts in a different direction. They are probably best used on motors that drive screws instead of belts. In a 3D printer, usually only the Z axis is screw driven, and rubber motor mounts won't do much to reduce noise there because the Z axis doesn't move much. If you want quality prints, you want to make things more ideal, not more sloppy. If the motors tilt, and the guide rails flex, and the frame flexes, how are you going to achieve the precision that quality printing requires?

Having managed a few Prusa machines at the makerspace in the past, I can tell you they are not immune to extruder clogs If you don't want clogs, don't print PLA. We also had a few spectacular print fails where the entire heater block ended up encased in plastic.

I don't know what your printer uses for linear bearings if it doesn't have smooth rods and LM8 bearings, but if you're up for that level of mechanical work, look into linear guides instead of end supported round rods. They are much more stable because they don't flex as much as the 8mm rods. A single linear guide can replace two round rails/bearings, so construction can be more compact, and it usually looks neater, too.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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DragonFire
Measure the belts too. One cheap trick manufacturers do is use quarter inch wide, which have a slightly different pitch to G2 6mm belts.

It's not a huge difference but it does not work as well as using correct belt size.

Good call. One of the them measured at 6.35mm (1/4 inch). I will give this one a replacement as and see what kind of results come from that. ty

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Driver chips soldered to the board are generally more reliable than those tiny driver modules that can't dissipate heat. It's usually easier and more accurate to set the motor current via the config file than to have to mess around with adjusting tiny, easily broken pots, while guessing at the motor current. Some people think "I want driver modules so they can be replaced easily when/if they fail.", but they're more likely to fail because they're little modules. What you really want is drivers that don't fail. If you buy a controller that uses driver modules, be sure to buy a handful of extras- you're going to need them. Most of the better controller boards have drivers soldered to the controller board and use the trinamic drivers that can reduce noise level through 256:1 ustepping. The Duet boards are very good.

That is exactly what I thought, and I never considered that built in drivers might have an advantage

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Rubber motor mounts can help reduce vibrations coupled to the printer's frame and resulting acoustic noise, but they also allow the belt tension to tilt the motor/shaft which affects the way the belt rides on the pulleys. Every time the motor reverses direction it tilts in a different direction. They are probably best used on motors that drive screws instead of belts. In a 3D printer, usually only the Z axis is screw driven, and rubber motor mounts won't do much to reduce noise there because the Z axis doesn't move much. If you want quality prints, you want to make things more ideal, not more sloppy. If the motors tilt, and the guide rails flex, and the frame flexes, how are you going to achieve the precision that quality printing requires?

again, I never thought of it this way but it makes sense. When thinking of printer mods, I lean towards better tramming and stiffer construction, but I had always though that rubber mounts would be a good way to dampen sound

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Having managed a few Prusa machines at the makerspace in the past, I can tell you they are not immune to extruder clogs If you don't want clogs, don't print PLA. We also had a few spectacular print fails where the entire heater block ended up encased in plastic. [/quote]
What is it about PLA that causes extra clogs?

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I don't know what your printer uses for linear bearings if it doesn't have smooth rods and LM8 bearings, but if you're up for that level of mechanical work, look into linear guides instead of end supported round rods. They are much more stable because they don't flex as much as the 8mm rods. A single linear guide can replace two round rails/bearings, so construction can be more compact, and it usually looks neater, too.

V-slot rollers. I thought they were okay but needed a little fiddling to get right, but since comparing to smooth rod I am not sure I can go back. I will look further into linear rails. Mgn12 right?

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Godzilleni
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I'm going to go a bit against the grain, because putting upgrades into a printer which effectively double its original cost or more seems counter-intuitive to me.

1. v-Wheels are quite capable as a linear motion system for a 3d printer. They do require maintenance but if properly adjusted should perform equally as well as linear rails or rods/lm8uu's. It's your money, spend it however you want.

2. firmware and slicer profile tuning are so critical to the end quality of your prints, prusa knows this and does it better than any other manufacturer than I am aware of so you get the best out of the box experience and reliability.

3. The DUET lines of boards are excellent but are really geared exclusively towards RepRapFirmware, they are generally WAY overspecced for an Ender3 type of printer. If you need excellent official customer support, this is hand-down the best for your money. I would argue that I've been building, using, tinkering, and modding various printers for 4 years now without EVER overheating or blowing up a stepper module. But poorly made main boards are easy to blow. I've found some of the more recent BigTreeTech (BTT) boards are actually pretty well made as they've tried to improve their brand through quality improvements. In your case a good board that would support either Marlin or Klipper firmware would be the BTT SKR Pico with board sized/formatted to work well with raspberry pi, or BTT MINI E3 v3.0. both boards have integrated drivers, 256x microstepping, firmware control for motor current and drivers are exceptionally well heatsinked.

4. You may want to consider checking out Klipper firmware, it is stable and I find it to be superior to Marlin in almost every regard and supports a wide range of aftermarket controllers. Including configuring your firmware without having to recompile, or worry about eeprom for changing settings. Along with some mature web control panels and advanced features such as input shaping (a feature also recently added to RRF).

5. Adding a second belt driven z-screw will help stabilize the z-axis and improve the consistency of layer stacking for sure.

Edited 1 time(s). Last edit at 03/19/2022 10:56AM by obelisk79.

I don't know why PLA causes clogs- it melts at a low temperature, so maybe it decomposes at a low temperature, too, and leaves residue that builds up inside the heater block.

I've been printing for 8 or 9 years and in all that time I might have used two spools of PLA. I used to print ABS almost exclusively, but these days mainly PETG, TPU, and occasional ABS. I haven't had a clogged nozzle/hot-end in 7 or 8 years.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I ran into one of my pictures of the plastic encased heater block on a Prusa printer. This would be failure of the first layer of the print to stick to the bed, not an extruder failure. I've seen this particular failure 3 or 4 times at the makerspace. When we train people we tell them to be sure and watch at least the first layer of their print before they walk away, but this happens anyway.



One thing I can recommend is to not put a bunch of decorative covers on the extruder to make it look more "professional". All that stuff gets in the way when you have to do anything to the extruder.

Edited 2 time(s). Last edit at 03/23/2022 07:55AM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

From my understanding, that kind of plastic blowout around the block is typically due to an improperly assembled hotend. Easy mistake to make, yet also easy to avoid.

That one looks like roasted marshmallow!

It's actually from the print not sticking to the bed. All that plastic came out of the nozzle.

One thing that I have found especially hard to drill into people's heads is that they should keep their grubby hands off the bed. For same reason, people insist on touching it to see if it's hot. It has always stuck me as strange that they don't also touch the nozzle to see if it's hot.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

People can be odd indeed.

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obelisk79
People can be odd indeed.

But often predictably so. If it says "WET PAINT", most will touch it to verify. If it says "HOT - DO NOT TOUCH", most will do the same. Removing the warning reduces the problem by at least 85%, and the other 15% get burned, painted hands. I don't know of any instance where anyone was killed or even seriously injured in either case, and they probably won't do it again.

My two year old son couldn't grasp the concept of what "Hot, don't touch" meant in regards to his fascination with incandescent light bulbs, until I finally let him find out for himself. You can't pad all of the world's sharp edges. Nor should you. Experience is the best cure for ignorance.

Edited 1 time(s). Last edit at 03/24/2022 06:49PM by rq3.

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rq3
You can't pad all of the world's sharp edges. Nor should you. Experience is the best cure for ignorance.

Wholeheartedly agree.

I have never had a clog like that but I have seen the first layer pop off and create a mess around the nozzle. The extruder keeps pumping fresh filament onto a layer that is attached to the nozzle and ... presto. That image is far beyond anything like I have ever had though. Thanks to this thread I have been looking into Klipper a bit and I like what I have read about it. Are there any klipper vs marlin reviews that I should be aware of? From basic descriptions, I cannot think of a reason that Marlin even gets mentioned anymore, except for maybe the need to add in a raspberry pi.
I am leaning towards the BTT boards as a price to performance leader. 32 bit board with trinamic drivers and sensorless homing. I am not sure what else I could ask for, but that seems a good start. Thanks again for the help guys

Take a look at RepRapFirware too. It provides a Web interface on suitable hardware and supports input shaping, without the added cost, complexity and startup time of a Pi. It has other features that Klipper doesn't have such as conditional GCode. It's available for Duets and for some SKR-based boards.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].