Advanced 3D Printing Tips & Tricks

In a Nutshell

Just for myself, I’ll document some advanced 3d printing tricks (for both FDM and SLA printers) I’ve picked up along the way so I don’t have to Google them and find that one comment from that one random person on page 5 of some forum to jog my memory. Maybe this will assist others?

How can I compile Marlin firmware without without VSCode nor Arduino? How to solve errors like missing U8-glib-HAL?

Use Docker. Here is a complete solution to build the firmware file with a single Bash script using Docker. You do not need to install VSCode nor Arduino to compile the Marlin firmware.

marlin featured

How can I remove a stuck part on the FEP without draining the resin? Is it even possible to get off a stuck part on the FEP in a vat of resin without a scraper?

Cure an entire layer and peel it off. Do not dump your resin back into the bottle which takes time (gloves, filter, funnel, towels, cleanup, etc.). Instead, leave the resin or add more resin, then expose the entire bottom layer for 60 seconds to UV with the test pattern tool.

Raise the build plate out of the way, unscrew and take out the resin vat carefully, and gently press on the bottom of the FEP edges while walking a slow perimeter with your finger (no glove needed). The cured layer will pop up along the edges. From there, you can use a spatula or plastic scraper to get just one corner of the cured layer and gently peel it away from the vat.

Replace the vat. No need to auto home again. Gently run the spatula or plastic scraper along the inside of the FEP to make sure the layer edges are gone. Use the spatula to place the cured layer into a holding jar instead of the garbage (you can melt it down with pain thinner if you like.)

How can I recycle Wash Station IPA (Isopropyl Alcohol) for reuse?

With a 10-micron aquarium sock and a UV lamp.

Take the metal basket out of the wash basin and set it aside. Clean it manually with nitrile gloves on using IPA in a separate area. Let the basin dry. Safety goggles and respirator on. Pour the wash bucket through the usual funnel and paper resin strainer (190 microns, used when you cycle vat resin) into a large glass container with an air lock that allows 405nm UV through (most glass will allow 75% of 405nm to pass, but you can test it with a handheld 405nm UV flashlight).

Either shine a bright UV lamp at the glass jar for about 30 minutes, or place the jar on a bright window sill for a few days; I have a 150W UVA lamp and it works fantastically.

With the UV lamp approach, the jar will look like foam filled it. That is because the suspended resin cured but did not settle to the bottom. No problem. Place the large aquarium filter sock in yet another glass jar – preferably bigger – and pour the foamy mix into it. You can then slowly pull up the 10-micron sock and see the clear IPA is left in the jar. Elegant, inexpensive, and simple. Turn the sock inside out and wash with soapy water to clean it for next time.

Coffee filters (~20 microns) clog up with the fine particulates; do not use coffee filters.

Should I use a magnetic flex plate for a resin printer? It seems smart and efficient to just twist the metal flex plate so parts come off.

No, don’t. It’s a clever idea, but resin and IPA will creep behind the flex plate, creep behind the magnet, and the whole plate/magnet will need to be washed frequently.

Also, there will be plate adhesion problems, and you will have to adjust your z-axis stopper if you can find it.

Plus, if there are any vacuum/suction/jumping issues with non-basic resin, the flex plate will buckle and your print will fall off into the vat of sorrow. I threw my flex plate out. Stay with the all-steel, solid, OEM build plate and scrape it after each print. It just works.

I like to have a few genuine, OEM build plates around so one is always clean for the next print.

What glue bonds two resin parts? Can I use Super Glue or Gorilla Glue?

You can use Super Glue. I use cyanoacrylate glue with no accelerator just fine to glue two halves of a ball together, for example. Gorilla Glue is overkill for resin prints because the bond strength greatly exceeds the part crush strength.

How strong is a Super Glue bond? It’s stronger than the cured resin, but even with “basic” resin, you will want an epoxy or enamel paint to strengthen the print whole print.

What glue bonds a resin part to metal?

You can use Super Glue. I regularly bond Neodymium magnets to UV resin parts and they hold very well, even when another magnet is nearby.

How can I sand an FDM-printed part? What grit sandpaper works well on PLA?

Use 400-grit wet sandpaper. 1000-grit is too fine and will take a long time, but I find wet 400-grit sandpaper with IPA smooths a part well. You will leave white marks when you sand a resin-printed part which can be minimized by rubbing the part with IPA afterward.

How can I protect a resin/plastic part from impact?

Coat it in Plasti Dip. Plasti Dip is meant for dipping metal in liquid rubber to coat tool handles in rubber. It works well for resin-printed parts such as balls and levelling feet. You need to suspend the part by a string or wire, dip it into a vat of Plasti Dip of any colour (even clear), and wait at least 30 minutes between coats with an average of 4 coats. Set a timer.

Tip: You may want to build a hook or tie point into your model that is recessed into the surface: when you fill it with Plasti Dip by way of dipping, you can cut off the excess rubber without accidentally exposing the surface of the print.

How to get Plasti Dip layers smooth on a curved part while drying?

Use compressed air. Holding about 10 cm away and moving closer as needed, force away the lumpy parts while drying each fresh layer of Plasti Dip rubber.

How to smoothen an already-dried, lumpy Plasti Dip part?

Use mineral spirits. Never use sandpaper of any grit. Put a small amount of mineral spirits in a shallow dish. With nitrile gloves on, dip your finger into the spirits. Rub the area you want to smooth out gently with your finger(s). The surface of the Plasti Dip will slowly re-liquefy and flow under your finger. When the Plasti Dip starts to feel tacky, dip your finger again and keep going. (ref).

Be careful not to rub too hard or else the rubber may come off and expose the print.

How to fix a punctured FEP? Can I use clear packing tape to patch a pinhole?

You can use clear packing tape temporarily. Just like patching a tire puncture, you can use clear packing tape to temporarily seal the backside of FEP. To make it last longer, cut the corners of the packing tape to make the patch more rounded. Prolonged use of such a mended FEP will cause the puncture to curl into the vat – this is only a temporary solution that can last several hours of printing.

Can I run power tools at the same time as an FDM (e.g. Ender 3) printer? Will sudden power draws affect my prints?

Yes, you can. As long as the breaker doesn’t trip, a good power supply like the Meanwell LRS-350-24 (on the Ender 3 Pro) has very good capacitors and can take momentary voltage drops without skipping a beat. It handles 24V at 350W. I have been using Meanwell power supplies for a while now, and love them.

How can I save on electricity when FDM printing in British Columbia?

Print half the model before midnight and the other half past midnight. In British Columbia, the residential rate is, as of 2022, $0.0950 per kWh for the first 1,350, then $0.1408 per kWh over the 1,350. If you print a long print every two days, straddle midnight.

If I build an FDM heat enclosure, how hot should it be?

Over 30℃. You don’t need to actively heat some aluminum enclosure; the 200℃ extruder and 50℃ hotbed will keep any enclosure warm and draft-and-dust free. I use a large grow tent and it works great, plus the warmth cuts down on humidity near the printer.

How can I quickly space the Z-axis motor?

Use two 1mm spacers. Place a spacer of desired thickness (0.5mm or 1mm) on each Z-axis motor screw to quickly add a gap to that stepper motor. Move the gantry up and down and confirm the lead-screw rod stays centered.

How can I prevent a scraping noise by a stepper motor?

Use a spacer. Unscrew the two grub screws connecting the lead-screw rod and the motor shaft, place a 1mm spacer between the motor and the connector, and tighten both grub screws. Remove the spacer. The rod connector no longer rubs against the stepper motor.

How can I use an inexpensive, fixed-focus HD webcam to watch my 3D printer?

Crack open the shell and manually focus the lens. I like the Jiga webcam at $30 with a 2MP CMOS sensor. Its problem is that its factory focus starts at 2 feet. This is no good for OctoPrint and OctoLapse. If you can, crack open the shell, use some force with a pair of pliers, and break the dot of glue holding the lens at its factory focus. Then you can twist until focus is perfectly at the hotbed center.

What is a quick way to clean the hotbed?

Scrape, sand, IPA. After each print, scrape off stuck PLA/PETG/ABS etc. with a metal scraper, then lightly sand with a small square of 1000-grit sandpaper (1000-grit to not send plastic dust flying). Finally, wet a tissue with IPA and wipe the hotbed. The printer is now ready for the next print.

How can enable ABL (auto bed-leveling) in Marlin using the BL-Touch probe with 25 touch points? I also want auto-leveling to be faster than the default speed.

Edit Configuration.h. Make sure these lines are as follows:

Save. Compile the firmware.bin. Copy the binary to the root of an SD card. Insert the SD card into the Ender 3 mainboard. The firmware will update. Remove the SD card.

My printer looks to be moving well, but no filament comes out. Why?

Check the extruder shaft grub screws and/or broken filament. In my case, the extruder was turning and the filament spool was twitching, but no filament was coming out. It turned out the grub screws on the gear that feeds the filament was loose, so the extruder would visibly move, the PTFE tube and filament spool would twitch, but no filament was extruding. Another time the filament simply snapped at the head of the direct-drive extruder.

The thermistor is wrong. There are dozens and dozens of temperature tables in Marlin for known thermistors. If you bought a dodgy thermistor from overseas, it might report 210℃, but the hotend is only 160℃, so the filament isn’t melting. Either purchase a new thermistor, or manually build a temperature table. For example:

How can I pause and resume a print?

Use GCode with OctoPrint. Use the follow snippets in the pause and resume sections of OctoPrint. Cura uses M82 (absolute extruder) so be sure to use M82 and not M83 in the following snippets:

How to prevent hotend thermal runaway? The error code is: Heater_E0?

The screw holding the thermistor is too tight. If the hotend screw is too tight, the temperature may melt the wires under pressure and cause a short to ground. Unscrew, wrap both wires individually in Kapton thermal tape, and screw the thermistor back into the hotend.

3d printer thermal runaway
3d printer thermal runaway

How can I print filament faster? Can I exceed 100mm/s?

Use a direct-drive extruder, and increase temperatures. I switched to a direct-drive extruder and removed the Bowden tube. Now I have a simple HDPE tube from the spool to the extruder (with a dust filter at one end). Next, increase the extruder stepper motor from the stock NEMA 17-32(mm) motor to 40 mm or higher; get one with higher amperage to take the harder and faster extruding and retracting. Next, make sure the power supply can handle 2 amps per stepper motor (including dual z-axis motors), as well as the hotbed and hotend: the Meanwell LRS-350-24 (24V, 20A) on the Ender 3 v2 is perfect. Finally, in Cura, increase the hotend temperature to 220℃ for PLA. Without any fan modifications, you can easily get 100 mm/s with superb prints.

Use an extruder with a 3:1 ratio for more torque. My other printer uses a Bowden tube with a 3:1 dual-gear extruder with e-steps set to 406 steps/mm and there is virtually no stringing, plus it prints quite fast.

Switch to 0.6mm nozzles and Cura 5. Cura 5 can slice a model accurately using 0.6mm nozzles, and prints are significantly faster even if the feedrate is below 100mm/s.

How can I remove an FDM-printed part? It is really stuck on the hotbed and hard to scrape at all.

Let the hotbed cool. When the hotbed gets back to room temperature, it shrinks a bit and the printed part will come right off like magic.

How thick should I make FDM container/box/case walls?

2.8 mm with a wall line count of 4 or more. Actually, a multiple of the nozzle diameter is best. So, for stock 0.4 mm nozzles, 2.8 mm is better than 3.0 mm to avoid squishing the filament to the sides by 0.2 mm in order to keep dimensional fidelity. Also, if the wall line count is 4 or more, then no infill is used with no time spent on micro zig-zagging. If the wall line count is 4, then both sides of the wall are drawn like so: 0.4 mm x 4 x 2 = 3.2 mm. However, only 7 lines will be drawn, so that becomes 2.8 mm.

How to fix layer shifting in FDM prints?

Slow down the print. Yes, your belts may be loose or tight, but we can pass over that because of our good maintenance routine. I found that on parts that require rapid jumping to give the part a certain pattern or texture, a speed over 100 mm/s causes my layer shifting. Also, the filament has a speed rating that I shouldn’t be exceeded by too much.

If you want speed and consistent layers, trying creating “individual setting regions” in Cura. It’s too advanced for a quick answer, but you can create regions that have individual settings. For example, you can set half a part to 20% infill, and the rest to 40%. Pretty neat.

How can I edit STL files from Thingiverse and GrabCad?

Install Meshmixer, Mesh Enabler, Autodesk 3DS, or Autoconverter. In Meshmixer (free), I find that you can cut off sections you wish to rework, save as STL, and them import into Autodesk Inventor or Solidworks. However, the mesh is just a representation in Autodesk Inventor, so use Mesh Enabler or 3DS to make a solid.

Cut STL object planes and resave
Cut STL object planes and resave

Why are my clear resin prints turning yellow?

Too much UV. Try to cure the resin part less for than 10 minutes in weak UV light (i.e. the curing station). If you use a 150W UV lamp, the part will definitely yellow in just a few minutes. Using a handheld 365nm UV flashlight works well to cure delicate parts. Just focus the light if your pen light is adjustable and blast the joints or small parts with UV light. Let the rest cure in weak UV light, but not sunlight.

Should I use Thingiverse? Why do Thingiverse parts for my printer often fail or are the wrong size?

Designs are supplied by hobbyists. Though well-intentioned, I’ve found that many 3D printer upgrades need to printed at 102%, need thicker walls, or are just dimensionally incorrect. I truly feel you can derive inspiration from Thingiverse, but it is far better to design your own parts. Another example is how a 20mm drag chain didn’t fit into several holders I once printed; it turned out the tolerances on commercial drag chains is very low: measure and design your own.

More to come…