Friction in a standard v. Capricorn bowden tube: More friction in the tube means less force pushing filament through the HotEnd

Push the pipe into the fitting, up to the pipe stop. If the Speedfit Pipe has been cut correctly the insertion mark on the pipe will be level with the collet head. The ‘O’ ring on the Superseal Pipe Insert provides a secondary seal against the bore of the fitting. A good connection has been made. An ‘O’ ring at the head of the insert and the shape of the stem, provide a secondary seal against the bore of the fitting. A combination of this and the main ‘O’ ring ensure a good connection. Bowden systems improve print quality because the resistance of the spool to unwinding no longer tugs on the print-head as it moves around" Your extruder system has a finite amount of pushing force. You want as much as possible of that pushing force to be used to generate pressure in your HotEnd, as it’s what causes the molten filament to actually extrude from the print-head (pretty crucial to 3D printing!).

The push-fit solutions can also be found in water purification systems. These food grade fittings have been designed specifically for fluid control and drinks dispensers meaning that when using water systems in offices and other public places, water is safe to drink, while systems are easy to maintain and repair. Although currently push-fit fittings are commonly associated with plumbing and heating, the plastic push-fit concept has originally been designed by John Guest for compressed air applications in 1974. And ever since then many industries have benefited from this small but mighty solution. Here are some of them:

The spool weight myth is countered because you get the same no-drag effect with a direct extruder by running a guide tube from the spool holder to the extruder in the normal way, thus keeping a constant filament length between extruder and spool independent of carriage position. Initially push-fit fittings were being used for fuel systems and now they are an essential part involved with low-pressure power steering systems and aiding the development of greener engines. Other things you can do to improve performance include having the shortest bowden tube possible, while keeping bend radius no less than around 150mm.The amount of “stuff” on the print-head is much lower, and takes up less space. This can mean a smaller print head, a larger usable print volume, more extruders on one print head, or any combination of these factors.

The stem of the insert gives greater rigidity of the length of pipe within the fitting, reducing the chance of leaks if a side load is applied. Don’t forget that bowden tubes can and do wear over time. Abrasive filament will gradually eat away at the inside of the tubing, and just the passage of filament with drive-wheel toothmarks on it will have an impact. Additionally, the ends where the couplings grip can get chewed up over time, but this is much reduced if you use our new collet clips. Retractions try to counter this by “pre-pumping” at the start of extrusion and relieving pressure at the end of extrusion. The more nuanced pressure advance algorithms do a conceptually similar thing, but are continuously compensating during acceleration and deceleration. Whatever control method you use, it is not possible to gain control authority over a system that is inherently less responsive. You can compensate for the errors to an extent, but you can’t eliminate them. Your extruder has a finite amount of speed and acceleration which it can use for compensating. Collet covers for use with standard Speedfit fittings, are available in white or in red or blue to allow colour coding of pipes. We have a new high-performance bowden tube , and ways of making our tube couplings grip the tube more securely using a pre-tensioning clip . These will make your bowden system more responsive and reliable. Read on to find out how. What is a bowden system?More lag/lash/hystersis/slop/whatever you want to call it. The extrusion system is simply not going to be as responsive as a direct extrusion system White or grey collet clips are used with standard fittings to prevent accidental pipe disconnection. To increase the stiffness of the filament spring we are introducing Capricorn PTFE Tubing; a new, higher tolerance tube, with a tighter 1.9mm internal diameter and added internal lubricant. This has a twofold benefit - it reduces sliding friction of the filament in the tube, but most importantly it makes the filament 'spring' stiffer, by quite a lot. The tighter internal diameter permits the filament to have far less flexion than in our standard 2mm ID tubing, meaning that it can't bunch or coil up. This really firms up the response of the whole bowden system. Because the filament has no space in which to bend within the tube, movement produced by the extruder is much more efficiently translated down the tube, into the HotEnd, and out the other side. Speedfit Fittings have a unique grip then seal construction made up of a collet with stainless steel teeth to grip the pipe and an ‘O’ ring to provide a permanent leak proof seal. Use of the Superseal Pipe Insert ensures a double ‘O’ ring seal.