Hey. I’m new to 3D printing. I’d simply buy Bambu Lab (BL) filaments if they were actually in stock. So, I’ve had to look elsewhere. I see that some filaments are branded as High Flow and others as High Speed. I’m wondering what’s the difference. My sense of it is that it’s tomato, tomahto.
As I understand it, speed is closely related to volumetric flow. The easier a filament melts, the higher volumetric flow one can achieve, the faster one can print, mutatis mutandis.
Am I correct in that it’s just branding, or is there an actual difference? Thank you.
Your printer has 4 motors. 3 control XYZ and are hooked up to belts. Those 3 control the “speed” of the machine, how fast it can move the toolhead to locations.
The fourth motor is the extruder. It is hooked to a gear system that grips the filament and moves it up or down. This controls the “flow” of how fast plastic is moving out of the nozzle, and how quickly retractions happens, etc.
Both systems are constrained - and the marriage of those constraints is the mathematical problem your slicer solves for. So in general, yes, you need good amounts of both to help reduce time spent. The slicer preview panels can help you discern if you are speed-constrained or flow-constrained.
The constraint on how fast you can lay down a given amount of filament is related to the nozzle size, temperature, viscosity of the melted plastic, along with the ability of your extruder to press filament forward with sufficient force to extrude it and your hot end to raise it to the desired temperature at that rate.
Filament manufacturers add various things to “pure” base plastics to improve one or more of those things. Rather than calling it something unappetizing like “copolymer mix with viscosity reducing additives” they slap “high flow” or “high speed” or even just “+” on the label.
That’s up to the mfrs recipe - Things like surface tension and viscosity effect how well the filament will remain laid down at high speeds, and melting properties determine how quickly the filament can be state changed - you could do massive flow out of a 0.8 nozzle or similar but not be able to go fast. Line width is the variable that changes the linear relation from speed and flow.
I would buy filament that you find (comparatively[1]) easy and reliable to print with enough strength and appearance for your objectives. Sometimes “hot and slow” is better in terms of strength or some other characteristic that is important. Since the price for a given base plastic in regular and modified is usually about the same, if the modified has been out a while and the older formulation is still available, there are probably reasons for some people to prefer the older formulation past habit.
For example TPU generally isn’t “easy” to print, but I find that certain formulations work better for me and my projects than others. ↩︎
I treat it the same with the PETG HS that I use , Primarily because BL advertises that their PETG HF was designed for speed and is twice as fast as their regular PETG,
So, I’ve had to look elsewhere. I see that some filaments are branded as High Flow and others as High Speed. I’m wondering what’s the difference. My sense of it is that it’s tomato, tomahto.