This upgrade uses a spring loaded pressure plate to uniform feed regardless of filament thickness. It also compensate some fast retraction problems I had in precedence.
I found that sometimes the filament you buy it’s not always “perfect”… the diameter should change just a little (0,1mm) but what I got recently was not that perfect…
Finding the right amount of pressure it’s a matter of experience, but if the diameter of the filament varies too much, it’s possible that sometimes it will be too loose or too “grindy”.
This is a really simple upgrade that solves brilliantly the problem.
SKILL: nothing special, if you bought a 3D printer this is a pice of cake 😉
TIME: 30 minutes if you drink a coffe meanwhile
TOOLS: nothing special, just scissors, screwdriver and a soldering iron
WHAT YOU NEED: 1 spring (11mm diameter), 1 M5 bolt longher than 7cm, 2 printable caps (I prepared theese: http://www.thingiverse.com/thing:36778)
Step 1: cut the head of the bolt to obtain a 6cm long thread
Step 2: cut the spring and keep a 3,5cm long piece
Step 3: print the two caps
Step 4: remove the original retainer and substitute the threaded screw with the new one (longher)
Step 5: thread the lower cap, the spring and the upper cap
Step 6: put back the original retainer
I also found that during a fast retraction, especially if it happens many times in a short time, could cause some problems.
A fast retraction put some extra strenght on the pressure plate and thus if you repeat this operation a couple of times on the same part of filament it’s not good at all. As you can see from the video I posted this little upgrade makes a good job solving this problem as well.