Our New 3D Printer Filament Runout Sensor

At Slant 3D, we build all of the machines for our printer farms. While most of the parts for the machine are manufacturered in house, there are components that we source...or used to.

One of the pieces where we used third party suppliers was the filament runout sensor for our machines. Filament runout sensors ensure that the machine is able to pause when a spool goes dry. That way filament and time is not wasted from a failure due to runout. (A problem that is dramatically compounded with hundreds of machines)

The sensor that we used historically was an off-the-self design that is sold by a number of 3D Printer supply sources. It is basically just a mechanical leaf switch in an injection molded housing. The main problem is that we have had continuous supply issues. Components have been miswired. Some have faded out overtime. And there is no way to access the problem easily when it occurs. So we designed a new filament runout switch. A nice simple one.

The Old Filament Runout Swtich

Our New Filament Runout Sensor

The Slant 3D Filament runout sensor is designed like our machines. Simple and easy to maintain. 

The sensor itself is still just a switch. But it is now a universal switch from suppliers that we trust and have used for years. It is clean and simple.

The secret to a good filament runout sensor is design. Make sure that the switch is always fully depressed and cannot wobble or go out of alignment, throwing false positives. We have been able to do this. 

Without the cost of injection molding we have been able to iterate on the design so that every single feature is optimized. The through holes are the minimum size possible. Holding filament in line and straight. The switch is only ever deactivated when filament is missing from the sensor. No wobbles or curves can throw a false positive.

Ultimately it is just simple. We took a standard switch and just designed a good filament guide for it.

Lastly. It has a lid. This means that loose debris or filament edges can be removed from the sensor if it somehow becomes jammed. On all other filament sensors this is almost impossible. And not only did we make a lid, but we labeled the feed direction.(Not that important but nice things are nice)

The Slant 3D Filament sensor will go up for preorder soon. And we will modify the mounting system so that it can work with as many 3D Printers as possible.

Look for it in the next few weeks.