1 Hardware upgrades for cheap bedslingers

Here comes a short list of cheap upgrades for old i3 bedslingers like the Ender 3. The idea is to spend no more than 20-30e in order to support the performance increase allowed by Input Shaping and Linear / Pressure advance coming with Marlin 2.1.2.1 or Klipper.

Generated on 2024-03-02 by Eaman

1.1 TLDR Essential parts

In order to sustain faster speeds your extrusion systems has to provide better flow, something in the range of 12-20mmc/s to archive print speeds of ~200-250mm/s with a line width of 0.4-0.7mm. You will then need better cooling for that increased amount of material, in the shape of one or two 5015 blowers.

A PEI sheet would be helpfull to accomodate the faster movements of the bed, both lighter and with better adhesion than glass if you are still using that. Using a glass bed would probably limit acceleration to ~3k and the limited bed adhesion would require the use of brim or glue for most prints.

So you need:

That’s as cheap as it gets, better options will come further ahead.

Despite common belief you may not need to upgrade the actual hot-end, the standard one with just a better / longer nozzle should be up to the task of providing enough flow for ~200mm/s speeds with a 0.4mm nozzle, that may not hold true if you plan to use bigger nozzles.

1.2 Better parts

You can search for these parts on Aliexpress for lowest price, Amazon or Ebay according to shipping time. Disclaimer: I’m not affiliated with any store so I’ll just provide general descriptions and key words to search, when multiple sellers are available the one with more orders and activity time should be preferred.

1.2.1 Extruders

BMG clone

The standard single gear plastic extruder is trash, the marginally better metal dual gear are not up to the task for ~200mm/s. The base line is going to be a BMG clone extruder, usually worth some 11e on Aliexpress (so maybe 18e on Amazon or Ebay). Look for one with hardened gears, as they have better traction and last longer than the standard ones.

If you plan to go direct drive a Sherpa Mini (can be bought as parts kit and 3d printed), Orbiter (again look for Triangle lab for a quality product), Voron Stealthburner (FYSETC comes to mind) would be better as they have less mass. Yet I would not bother with those as the limiting factor for the cheap bedslingers is the weight of the bed therefore there’s no point in spending much on a ultra-light extruder as the acceleration is going to be limited anyway by the Y axis. If you are on bowden there’s zero need for a light extruder.

Better advice is to buy cheap and keep a spare, a BMG clone has been the best seller for years so it’s cheap, there are spare parts available (gears), it has proved to be reliable in years of usage. On the other hand if you want fancy ultra light you should not cheap out, those models also require an expensive pancake stepper motor.

1.2.1.1 Small Step Motor for direct drive

You don’t need to buy one.

As said the limiting factor is the bed weight so it’s OK to put your old extruder motor on the gantry when you go direct drive, you probably won’t be able to do more than ~6-8k acceleration so you don’t need a light motor.

Yet if you have an original Ender 3 you got an over sized step motor for the extruder, in this case there are two options:

  1. Swap the big motor for the X or Y axis, you could actually use more torque there.

  2. Get a smaller motor, no need for a pancake, one nema 1742 stepper motor 23mm would do.

1.2.1.2 So what about Direct Drive?

Direct Drive is good, it provides better control on extrusion and reduces retraction down to 0.30mm (from some 1.5mm with bowden, now that faster travel speed and acceleration and better cooling help too), this means both better print quality and faster times. Also it doesn’t cost a cent: you can print an adapter with your printer.

Direct Drive

In the picture: same GCODE, same printer same filament but DD on the right and bowden on the left, printed in 22m on a Ender 3.

The issue with DD is that you should have dual Z in order to keep the layer height consistent as the weight of the motor + extruder is not on the far left of the gantry anymore helping to reduce sagging, now that mass is rocking fast along the whole X axis.

1.2.2 Nozzle

CHT like nozzles should provide some 20-30% increase in flow paired with a decent extruder even better if in direct drive mode (it takes just a printed adapter). An other option may be to get a volcano nozzle and use that on you normal hot-end, it works yet you will have to adjust end-stop and fan ducts for the increased length of the nozzle.

CHT clone nozzle

A volcano nozzle may be overkill, at least on my printer a mid range 16mm nozzle does provide enough flow to print 0.7mm line width with for 0.25mm layer height, as much as I would ask from a 0.4mm nozzle setup for solid infill.

Search for:

  • Clone CHT Brass Nozzle

  • Brass Surface Electro plating Nozzle These are some weird ones: length is 16mm so you will have to adjust Z end-stop and fan ducts, yet they are not CHT (which may help with retraction), they are electrocoated (helps with PETG and helps to keep the nozzle clean), they are actually pretty cheap so easily disposable. Also 0.3mm and 0.5mm are reasonable options for some more details or faster prints if you are not looking for trouble.

  • Clone CHT Volcano Nozzle Brass : longer, you will need to adjust z off-set and modify your fan ducts.

1.2.3 Fans and blowers

More material extruded requires more cooling, that can be archived by either quantity or quality, if we keep an eye on cost and noise. Oil / hydraulic fans are cheap and quieter but less preforming, so just get two of them. One hi quality ball bearing blower can be noisy like a small jet but it’s more compact if you already have a bed leveling probe.

5015 blower

Once again the weight on the gantry is usually not a big deal when compared to the bed so it make sense to look for a double 5015 with lower RPM if you want to save money and have a quiet printer. On the other hand one fast blower means less mass to move around but comes with an hi pitch sound and price tag.

Same goes for the hot-end: it may be worth it to mount a slower 4020 rather than an expensive hi RPM 4010, yet the original 4010 should suffice.

Always check your voltage before buying, 12v or 24v, check your old fan or the PSU reported voltage.

Here’s some examples:

4020 fan for hot-end:

Extra fan for cooling the whole print:

  • 6015 for side cooling

1.2.3.1 Fan ducts

You can print new fan ducts, even better design your own. For pre made models I would recommend:

  • MiniMe for essential light build, it works with any Ender 3 like hotend.

  • Dual Satsana (or single) for bigger build with easy customizable separated ducts.

fan ducts

1.3 Bimetal heat breaker

For printing just PLA at low temperature nothing is better than an in-line bowden that goes from the extruder straight against the nozzle, yet low quality white bowden can be too loose, Capricorn or similar better quality 1.9mm bowden have better temperature resilience for printing PETG.

bimetal heatbreaker

Nevertheless in line bowden is a trouble maker, it can cause filament leakage if not cut and mounted in the right way, can cause retraction problems (maybe due to a bad pneumatic coupler that comes with a cheap bowden), you have to check often that it doesn’t get burnt on the nozzle end.

Enter bimetal heat-breaker : no more worries with temperatures higher than 235c, no more need to babysit the end of your bowden. This is a cheap solution to what was an endless cause of troubles for the old extrusion systems. Search for: Bimetal CR10 Ender Heatbreak, for Ender 3 hot-end you want the smooth version.

1.4 Expected results

17 minutes benchy on Ender 3

What we want is to reduce print time, yet what we talk about most of the time is print speed.

Print speed is a measure of how fast you can print each feature as perimeters, infill, it is limited by how much material you can extrude in a second, expressed as max flow: when you try to make your printer go faster than that you get under extrusion. To know the max flow of your extrusion system you may do Orca Slicer max flow test, that does a real print so you also see if your cooling is up to the job. When you deposit much more hot material you also need more cooling otherwise your new line will squish the previous still soft extruded layer.

When you find your Max Volumetric Speed you can put that value in your slicer to limit the actual max speed for any line width you are going to use. If you’d rather see a max speed in mm/s you can use a max volumetric flow calculator , that should translate to something like 200mm/s .

flow

The actual speed that you can archive during a print depends on the acceleration that you your printer mechanics allows before going into layer shifting: if you have very limited accel like 500mm/ss it will take more time / space for your extruder to reach hi speed, hence only with big prints you get a chance to reach hi velocities. This means that without decent accel fabulous reported speeds like 800mm/s are almost meaningless.

With very small prints an other essential factor is what Marlin calls jerk, the ability of you printer to change direction quickly. That can induce layer shifting at hi values (>15mm/s). Linear Advance in Marlin can also interfere with you acceleration target (Pressure advance in Klipper does not).

Yet the most important feature for acceleration, hence hi speeds, is Input Shaping, that is the secret sauce that makes your print quality decent when you use higher acceleration than you used to. IS drastically reduces the ringing / ghosting resulting from hi acceleration movements allowing you printer to use as much acceleration as hard layer shifting allows.

The other important software feature to mention is Linear / Pressure Advance, which takes care of the extrusion flow / pressure in order to obtain sharp corners and avoid weird oozing while printing at hi speeds.

That’s how you can reach hi speeds quickly even in small prints, avoiding artifacts and rounded corners eventually reducing print time.

Final notes: be aware that print speed is different from travel speed, with the latter meaning movements without extrusion. It’s not uncommon for some manufacturer to brag about max speeds of some ludicrous values like 500mm/s: those are usually travel speeds if not properly specified as print speeds. Quite often the printer can’t extrude that fast, heck most common filaments won’t allow speeds higher tha 200mm/s, some like TPU will always need ultra low print speed. Even when you get actual print speeds of say 250mm/s those may be just for the infill while for the external perimeters may be as low as 120mm/s to obtain decent quality. So it’s all fun and games when we chat of speed (and let’s not get into layer height or extrusion width) but what you should care about is the actual print time and print quality when you go fast.

1.5 Quality of life items