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Build A 3D Printer Workhorse, Not an Amazing Disappointment Machine – Hackaday

by • July 5, 2016 • 24s Comments

3D printing equipment have become awe-inspiringly bargain-priced, you can get a fully workable-bodied unit for $200 – in fact without throwing your money down a crowdfunded abyss. Looking at the people who yet buy kits or in fact create their own 3D printing device of scratch, investing far additional than those $200 and so many hours of work into a machine you can buy for bargain-priced, the question “Why the heck may you do which?” may justifiably arise.
The answer is easy: DIY 3D printing equipment done right are rugged workhorses. They work every single time, they nat any time break, and in fact if: they are an inexhaustible source of spare parts for themselves. They have precisely the high end and functionality you create them to have. No clutter and nothing’s missing. But, the term DIY 3D printing device, in its current commjust accepted use, in fact means: the first and the last 3D printing device a fewone at any time created, which frequently ends in the awe-inspiring disappointment machine.
This post is dedicated to unlocking the full future in all of these creates, and to turning approximately any combination of threaded rods and plywood into a workshop-grade piece of equipment.

Taming Shaky Frames
The age of the shaky Mendel threaded rod frame is long over, it has been replaced by the age of shaky single-sheet Prusa i3 frames. Decent printing outcomes require a darn sturdy frame, so add brackets and stabilizers wherat any time you can.

Prusa Mendel unstabilized (image source)
Prusa Mendel unstabilized (image source)

Mendel with stabilizing board (image source)
Mendel with stabilizing board (image source)

Prusa i3, single sheet unstabilized (image source)
Prusa i3, single sheet unstabilized (image source)

Prusa i3, wood fashion with stabilizers (image source)
Prusa i3, wood fashion with stabilizers (image source)
If you are createing a cube-fashion printing device of aluminum extrusion, use angle brackets to stabilize the frame. If you are createing a Prusa i3 variant, manufacture sure you are either getting a frame with stabilizers or add stabilizers later. If you are createing a classic Mendel, add stabilizer boards to the cross struts.
Facing 3D printed parts
PLA is a horrible material choice for the 3D-printed portion of a DIY 3D printing device, first for it’s low melting point, and 2nd for its brittleness. Almany any material can perform advantageous, but at really least ABS parts can last forat any time. Print them really hot – at really least 255 °C to get a excellent layer adhesion and they can nat any time fail on you. Nat any timetheless: Always store a set of spares, for the reason you can. It requiren’t be a 3-pack.
Yet, the absolute accuracy and surface high end of 3D printed parts is not generally as polished as the aluminum extrusion and sheet materials they attach to. When you attach a 3D printed part to a flat surface via screws, you have all but two versions to get a solid connection: Make the screws really tight – which approximately always breaks the 3D printed part – or use a satisfactory grit sandpaper to flatten the contact surface of the 3D printed part to get a excellent contact between the two. Once the screws apply a reasonable-bodied amount of pressure, the static friction between the two surfaces takes over and provides a high resistance to shearing forces.

Unsanded left, sanded right, belt holder for Prusa i3.
Unsanded left, sanded right, belt holder for Prusa i3.

The static friction between flat contact faces provides higher resistance to shearing forces.
The static friction between flat contact faces provides higher resistance to shearing forces.

Unsanded left, sanded right, Z-motor mount for Prusa i3 rework.
Unsanded left, sanded right, Z-motor mount for Prusa i3 rework.
Drive systems
In conjunction with a rigid frame, both belt drives in various types of configurations (except for the H-bot) and spindle drives can deplete a repetitive accuracy which exceeds the requirements of FDM in the X and Y way by magnitudes. But, the high end and longevity of any drive system depends a lot on the high end of the involved components. Eccentric pulleys or couplings, as well as components which commence backlash, are the many common pitfalls here. Grinding belt teeth can cause vibrations, so manufacture sure all belts are running in the center of their pulley and idler tracks. Use flanged idlers or at really least washers to prin factt the belts of rubbing against other parts of the printing device.

Eccentric, wobbly, low-high end GT2 pulley with backlash (left) / high-high end GT2 pulley (right)
Eccentric, wobbly, low-high end GT2 pulley with backlash (left) / high-high end GT2 pulley (right)

Flex couplings (upper right) work just satisfactory, but their flex affects the positioning accuracy. Cardan joints (bottom) compensate for small offsets without flexing.
Flex couplings (upper right) work just satisfactory, but their flex affects the positioning accuracy. Cardan joints (bottom) compensate for small offsets without flexing.
For the Z-axis, it’s worth mentioning which the high end improvement you may assume of a stepper motor with integrated ACME lead screw shaft over the common threaded-rod-on-a-flex coupling solution is a fewhow insignificant – in fact in terms of longevity. Stainless steel M5 threaded rods in the Z-axis allow for excellent printing outcomes and last for many years, in fact when exposed to the steady stress of auto bed leveling. In this case, the budget solution may be excellent adequate. Of course, dimensionsable-bodied and heavy printing device assemblies do indeed require proper leadscrews.
Linear guides
As long as your create does not exceed the typical dimensions and mass of a computer desktop 3D printing device, avoid via linear ball bearings in the X and Y axis, as they are a really common failure point. Their high end varies excellently depending on the developer, and in fact if the bargain-priced shot works seemingly excellent in the beginning, they won’t last for long. 3D printed plastic debris and in fact fragments of their own assembly can sooner or later cause them to block. Tribological, polymeric slide bearings are the way to go here. They are self-lubricating, maintenance-free and virtually last forat any time, at really least by the standards of linear ball bearings. They are in addition on the market in Japan standard compatible form facts as drop-in replacements for the commjust utilized LM8UU.

The LM8UU and its tribological counterpart
The LM8UU and its tribological counterpart

Two Prusa i3 rework X-carriages in comparison: LM8UU (left) and polymeric slide bearings (right)
Two Prusa i3 rework X-carriages in comparison: LM8UU (left) and polymeric slide bearings (right)
Instead of two LM8UU, one LM8LUU is frequently the advantageous choice.
Instead of two LM8UU, one LM8LUU is frequently the advantageous choice.
Don’t use multiple linear bearings in line to increase the angular stability of a carriage. There are prolonged versions on the market for approximately every linear bearing type , for example, use the LM8LUU form factor instead of two LM8UU.
Motors and drivers_MG_0143$3 difference, double printing resolutionEven if you are on a budget, ponder of via stepper motors with a 0.9° step angle instead of 1.8° for the X and Y axis and for any ungeared extruder. They can most likely cost you $2 or $3 additional a piece, but they double your mechanical resolution, which can be incredibly visible. Microstepping is excellent for reducing vibrations, but – contrary to talked about understanding – does not increase the effective printing resolution. The next images of Yoda heads show the high end difference really unquestionably. They are printed at 0.1 mm layer height on the really same Prusa i3 of the really same G-Code — the just difference is the physical step angle of the motors.

0.9° stepper motors, 8x microstepping, 3200 pulses/rev, 80 pulses/mm
0.9° stepper motors, 8x microstepping, 3200 pulses/rev, 80 pulses/mm

1.8° stepper motors, 16x microstepping, 3200 pulses/rev, 80 pulses/mm
1.8° stepper motors, 16x microstepping, 3200 pulses/rev, 80 pulses/mm

0.9° stepper motors, 8x microstepping, 3200 pulses/rev, 80 pulses/mm
0.9° stepper motors, 8x microstepping, 3200 pulses/rev, 80 pulses/mm

1.8° stepper motors, 16x microstepping, 3200 pulses/rev, 80 pulses/mm
1.8° stepper motors, 16x microstepping, 3200 pulses/rev, 80 pulses/mm _MG_0129-compIt is a dirty hack, but it’s advantageous than driving two motors of a single driver.The rated current of your stepper motor drivers must be able-bodied to donate the rated current of the stepper motors, as the stepper motors can just donate their full torque at which current. Leave a margin of 20% to prin factt constantly maxing out your drivers. Even if a few retailers ship Pololu-fashion driver modules (i.e. A4988 and DRV8825) with (wrong-dimensionsd) heatsinks and thermal adhesive pads (of questionable-bodied high end), these heatsinks usually do additional injure than excellent. Leave them out and stick to the 20% current margin, and you can always get the full torque.
Besides which, don’t wire multiple stepper motors to a single driver, especially the small Pololus. If you can’t get your hands on a proper port duplicator with buffer capacitors for every driver, a bargain-priced and fully useable-bodied workaround is soldering female headers to one Pololu driver, add male headers for the motors, and backpack a 2nd on top of it.
Controller Board
The particular choice of 3D printing device controller board manyly depends on your individual requirements in terms of pure functionality. If you want a plug and play machine which works every time in any environment, avoid clones of Arduino based boards or other products which use bargain-priced usb-to-serial bridge replacements, such as the CH340/CH341. They may in facttually work, but long term plug-and-play driver assist for all significant operating systems can be a fewthing which’s worth paying for since it in facttually becomes part of the user experience.
Thermistors And Thermocouples
Know your components and just use temperature sensors which come with a trustworthy datasheet. Otherwise, the measured temperature can just be a slightly advantageous guess. Make sure the sensor has a excellent thermal coupling to the heated bed or hotend heater block to allow the temperature controller to store the temperature steady. Thermal compound is the way to go here. NTC Thermistors typically don’t survive temperatures above 300° C required to print a few engineering plastics, you are locked in with thermocouples. Besides which, whether you measure the temperature of the heated bed and hotend with an EPCOS NTC, a Vishay NTC, a Semitec NTC or a welded tip K-type thermocouple does not necessarily matter, they are all accurate adequate.
LCD ControllersReprapDiscount SmartController (by Reprapdiscount, image source)ReprapDiscount SmartController (by Reprapdiscount, image source)An LCD controller with SD-card reader turns your 3D printing device into a stand-alone factory. The classic RepRap Discount SmartController with a non-graphical display can perfectly
do for many configurations. There are clones around which work just satisfactory when utilized with the provided RAMPS adapter, but a few of them have their connector column flipped 180°, so pay attention when you hook them up to boards with dedicated EXT ports for the display panel, such as the RUMBA.
The click-and-scroll menu many firmwares provide for the common LCD controllers may be a bit cluttered and dissatisfactory to use, but which can be fixed really easily and we will cover which later in this post.
OctoPrint
A Raspberry Pi loaded with OctoPrint, perhaps in fact with an LCD touch screen, excellently improves the ease of use and productivity over the sparse LCD controller. It lets you send G-Code directly of the slicer to the printing device over the air and allows for you to conveniently control your printing device through a amusing user interface. But, it does add sat any timeal failure points to the machine. Whilst the SPI connection between the SD card and the microcontroller is a fewhow much bullet proof, you can approximately pretty experience a frozen Raspberry Pi or a hung OctoPrint sooner or later. It is yet rare, but if you are via OctoPrint to stream G-code to the printing device, manufacture sure you add
M85 S30; activate 30-2nd idle timeout
at the really beginning of your begin G-code to activate the idle timeout and
M85 S0; deactivate idle timeout
at the really end of the end G-code to deactivate it again. The 30-2nd timeout can kill the printing device and shut off all heaters in case the OctoPrint host freezes or otherwise stops sending commands preceding the print finishes as scheduled.
Hotend
ABS layer bonding at 280° printing temperature is sturdy as hell and manufactures printing dimensionsable-bodied, tough ABS models without cracking and warping on the first take on a breeze. Full metal hotends are the way to go here, as PEEK insulators and PTFE liners which revery down to the melting zone begin degenerating at much lower temperatures. So, use a full metal hotend and at really least a 40W cartridge for swift heatup time. Make sure the hotend sits rock-solid in it’s mount on the print head.
Extruder
Bowden extruders do have a sure backlash, but which’s not necessarily a problem when printing ABS, PLA and Nylon. Yet, the 1.75 mm variants of flexible materials such as (insert distinctive term here)Flex are a fewhow much incompatible with Bowden extruders and at most incredibly troublea few. If you are planning to work with these, use a direct drive extruder. Even when via a direct drive extruder, manufacture sure the filament is donateed to the extruder through a Bowden tube which is safely attached to a tube fitting on the spool holder. Setups, in which an extruder on a flimsy linear guide pulls the material right off the spool typically donate poor outcomes as the pulling force unpredictably deflects the print head during the print.All shown drive gears and hobbed bolts work excellent, although many regular hobbed bolts (right) wear out quick. Go for hardened steel.Go for hardened steel and sharp teeth. The MK8 drive gear and the black hobbed bolt shown above are just examples. Most regular hobbed bolts (right) wear out after the first meters and suffer of filament slip.Most 3D printed extruder assemblies, such as Wade’s extruder or AirTripper’s Bowden extruder work just as well as the additional expensive ones you can buy. The many significant factor for the consistency and reliability of the extrusion is the drive gear. Go for a high-high end, hardened steel drive gear or hobbed bolt, with sharp teeth and excellent grip.
Heated Bed
Long heat up times are a productivity rad, and to revery the temperature swift – within 3 minutes or so, a regular PCB heated bed requires to have a power density of of 1+ W/cm2 (6.5 W/in2). To revery 110° (230 °F) under normal conditions at all, a heated bed should donate a minimum power density of of 0.3 W/cm2 (2 W/in2). If you want to print materials like ABS, which require a high bed temperature, take the necessary wattage of the heated bed relative to its dimensions into account.
Single sided PCB heated beds tend to breathe up and down, due to the non-uniform thermal expansion of the copper traces and the board material, which can outcome in a surface finish which is affected by banding patterns. The animation shows the issue really unquestionably:single_doubleSingle-sided PCB heated bed (left) / Double-sided PCB-heater (right)Since high-high end prints rely on a Z-positioning accuracy in the tens of microns, in fact minor temperature fluctuations can cause a single sided PCB heater to commence unwanted artifacts. Use double sided PCB heaters or other alternatives which don’t suffer of this issue (i.e. silicone heater mats attached to a solid slate of aluminum), along with a well-tuned PID control loop.
Modern heated beds, such as the Prusa MK42, deplete a additional uniform temperature distribution by compensating non-uniform heat losses with a non-uniform power density, which assists a lot with producing dimensionsable-bodied structures stick to the create plate in its corners. In any case, always use a thermal cutoff fuse attached directly to the center of the bottom side of the heated bed.heatbedsThermal image of legacy Prusa MK2B (left) and new Prusa MK42 (right) (by Josef Prusa, image source)The heated bed must be mounted rock-solid to the frame or carriage it rests on. Don’t use loose adjustment screws with wobbly springs to mount them, as they can seriously affect the printing high end. Ideally, bolt the heated bed down as straight as possible and use auto bed leveling for the satisfactory adjustment.
Enclosed create chamber
Enclosing your printing device in a box prin factts draft and the retained heat allows for you to print dimensionsable-bodiedr objects of ABS with fewer distortions. The enclosure itself can be anything of a dimensionsable-bodied adequate box or a attractive acrylic printarium. As long as the heat stays within, it can just work. Keep the electronics of your printing device outside the heated create chamber to prin factt overheating of the motor drivers and power donate. Mind which actively heated create chambers in addition require actively cooled hotend-heatsinks.terrariumDual enclosed create chamber with glass sliding doors of a $50 OSB terrarium, for the reason, why not?Don’t add insulation material to the underside of your heated bed, since it decreases the overall heat output. Passively heated create chambers without excessive insulation can easily revery of 40° C or additional, just by retaining the heat of the heated bed. Keep maintenance effortless by producing sure the enclosure can be removed without disassembling the whole thing, and well, a door may be really great. In any case, avoid draft. When printing ABS and HIPS, in fact an improvised enclosure or just a little cabinet is advantageous than none at all.
Printing Surface
Regular window glass plates or mirrors are indeed able-bodied to endure high temperatures, but at 110° C the slightest impact lets them shatter. If you print on glass, which works excellent for materials like PLA and PET(-G), use borosilicate glass. For printing ABS, HIPS, and in addition PLA, a Polyetherimide (PEI) printing surface is rightfully celebrated as the most version. ABS sticks to it rock-solid during the print, and yet just pops off afterward. HIPS and PLA work just as well._MG_0195From right to left: 1/8″ glass fiber reinforced PEI plate, 1/4″ Garolite plate, Prusa MK2 heated bed, Makertum MK1 heated bedsBut, not just is PEI an expensive material with kilogram prices in the hundreds of dollars, it is in addition in low donate, which led to increased use of thin PEI adhesive movies. These movies do offer the same excellent adhesion and printing experience but are really fragile and easily get damaged. For heavy workshop use, use a 1/8“ PEI sheet instead. It can be slightly additional expensive but can last forat any time and can in fact be re-faced on a CNC mill once it shows wear. For an in fact printing surface, the PEI sheet must be stabilized, preferably by gluing it to a sheet of borosilicate glass or aluminum with the assist of a heat resistant transfer adhesive tape.
Don’t use heated aluminum printing plates with just a thin movie of PEI or Kapton on them. The high heat conductivity of the aluminum overshoots the goal of storeing the contact layer at temperature and heats through the entire print object to a point where it usually gets too soft to assist itself.
It is worth mentioning which the most known printing surface for Nylon is yet Garolite (aka. Tufnol). Nylon adheres well to it and in fact dimensionsable-bodiedr Nylon parts can be printed reliably on Garolite.
Auto Bed Leveling / Automated Mesh Bed Leveling
Whilst the classic servo-deployed probe always worked a fewwhat excellent adequate, the many versatile, accurate and reliable-bodied sensor type for auto bed leveling is the contactless capacitive distance switch. Many creates, especially ones with a metal create plate (i.e. the Prusa MK42) or carrier, yet use inductive sensors, but these sensors ignore non-metallic printing surfaces (such as a sheet of glass, PEI or Garolite) and just respond to the underlying metal sheet. Whilst this can, of course, be accounted for with an offset, which offset is rarely constant and uniform. Besides which, all contactless distance switches have a sure accuracy, typically of 10% relative to an adaptable-bodied trigger distance. Mount them with a short trigger distance, perfectly 1 or 2 mm, to get the maximum accuracy. Of course, any sensor requires to be mounted rock-solid to the print head for accurate probings.
Firmware
There are sat any timeal excellent firmware projects out there, with the many celebrated ones being Marlin and Repetier. Marlin and Repetier have really various approaches when it comes to their configuration. Marlin clones of a GitHub repository with two well documented and commented configuration files, one for the basics and one for the high end settings. Repetier in contrast uses a website which lets you compose your firmware settings in a graphical web interface and download the pre-configured sources. These sources in addition contain configuration files, but they aren’t really as well documented as Marlin’s counterpart.
When it comes to showcases and functionality, Marlin offers fewer showcases, but a rock-solid highly configurable-bodied and reliable-bodied platform worthy of a workhorse 3D printing device. In contrast, Repetier offers many experimental showcases, which include but not limited to virtual extruders for color mixing. It is the perfect firmware for exploring the frontiers of additional exotic 3D printing applications. On the other hand, not all of its plentiful showcases are always well documented, which is bound to cause trouble if you are just looking for a fewthing clean and reliable-bodied for workshop use.
Temperature Control Algorithms
Only a steady temperature lets you print high-high end models without banding and artifacts. A easy bang-bang temperature control switch does not provide the necessary temperature stability. The easiest and most way to deplete a steady hotend and heated bed temperature is a PID control loop, and both Marlin and Repetier offer which version. They in addition offer a PID autotune program, which can iron out any ripple in your temperature curve without compromising heat up times or overshooting too much. Repetier in addition offers an alternative dead time control algorithm, which in many cases works just as well. But, the accuracy and effectiveness of a dead time control loop depend on the ratio of effective dead time and the polling/update interval of the control loop. This outcomes in poor temperature stability on high-power heating elements which take place to have a dead time in the tens of milli2nds. Just use PID.
Cluttered LCD controller menus
The standard Marlin or Repetier firmware with activated display assist manufactures approximately every control version on the market through the scroll-and-click menu. It is deplete, but in addition cluttered, and lets you navigate through four levels preceding you can move an axis.The Marlin menu (simplified, by open-electronics.org, CC-BY-SA, image source)The Marlin menu (simplified, by open-electronics.org, CC-BY-SA, image source)For workshop use, just a fraction of the entries are in fact required. Just remove unnecessary entries in the firmware source code. In the source of Marlin, which can be easily done by commenting out unnecessary items in the pretty self-explaining ultralcd.cpp.
/* DISABLING “CONTROL” MENU MENU_ITEM(submenu, MSG_CONTROL, lcd_control_menu); */
You can in addition simplify the move menu to skip the feed rate selection:
/* DISABLING ORIGINAL MOVE MENU static void lcd_move_menu() { START_MENU(); MENU_ITEM(back, MSG_PREPARE); if (_MOVE_XYZ_ALLOWED) MENU_ITEM(submenu, MSG_MOVE_10MM, lcd_move_menu_10mm); MENU_ITEM(submenu, MSG_MOVE_1MM, lcd_move_menu_1mm); MENU_ITEM(submenu, MSG_MOVE_01MM, lcd_move_menu_01mm); //TODO:X,Y,Z,E END_MENU(); } */ // ADDING CLUTTER-FREE MOVE MENU static void lcd_move_menu() { START_MENU(); move_menu_scale=0.1; MENU_ITEM(back, MSG_PREPARE); if (_MOVE_XYZ_ALLOWED){ MENU_ITEM(submenu, MSG_MOVE_X, lcd_move_x); MENU_ITEM(submenu, MSG_MOVE_Y, lcd_move_y); MENU_ITEM(submenu, MSG_MOVE_Z, lcd_move_z); } END_MENU(); }
Fire Prin facttion
It is rare, but 3D printing equipment can catch fire. Use the safety showcases provided by the firmware, but don’t solely rely on them. Both plain MOSFETs and solid say relays typically fail in their conducting say, which can outcome in runaway heating with disastrous outcomes. Thermal cutoff fuses are $1 components, but they are well able-bodied to prin factt a runway heated bed of turning your workshop into a crater._MG_0150This $1 component is priceless. Use thermal cutoff fuses.External Factors
Uninterruptible Printing
If your mains power line is unsteady, or if highly inductive power equipment take places to be turned on in the same workshop – bargain-priced handheld plasma cutters for instance – it’s a excellent thought to operate your printing device of an UPS (uninterruptible power donate). Even a short power failure during the printing system ruins the print, and a small bargain-priced UPS can assist you out in which case.
Filament Quality
Apparently, producing excellent filament is a little additional rigorous than feeding pellets into a heated a fewthing with an auger. It requires accurate measurements and a closed feedback loop to in fact store the tolerances low. Filament defects I discovered in bargain-priced, low-high end filaments range of trapped air bubbles, variations in properties, color, and diameter. I in fact discovered a spool of ABS which faded into PLA half-way through. All this does not offer to reliable-bodied high-high end printing, and if half of the prints fail, it’s not in fact bargain-priced. So manufacture sure you get a excellent filament which benchmarks your machine’s capabilities.
The Extra Mile
One excellent advantage of DIY printing equipment is maintenance. The availability of spare parts and documentation manufactures it possible, but it should in addition be fun to work on the machine. Tidy wiring, cable-bodied guides as well as a consistent color code for voltages and signals across the printing device can save you a lot of time, frustrations, and magic smoke as soon as you require to revisit the internals of your machine a year or two after you first created it.
I hope you loved this compilation of learnings of additional than 20 one-of-a-kind 3D printing device creates. Most open source projects maintain a detailed assembly guide but miss out on the details which manufacture a machine a excellent, reliable-bodied, and fun-to-use piece of workshop equipment. The article has grown long, but hopefully fills adequate of the gaps to turn any DIY 3D printing device project into a good results. It is in addition bound to be indeplete, so add your own findings in the comment section!


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