Friday, 8 July 2011

Loctite, Castrol, spacers, nut-Y-less, RAMPS and a Mega issue

Managed to squeeze in a little progress this week...

Some of the nuts on the frame were already working loose (as of last weekend), so after skimming the forums for suggestions - I ordered 10ml of Loctite 243 ThreadLocker. As of yesterday, I've now put a dab of loctite under each nut on each vertex, plus those around the Z-motor mounts. This also gave me the chance to fine tune the distances between each vertex.

Lithium Grease
The smooth rods were fairly grubby and there was far more friction on the X/Y axes than I'd like. So.... a few minutes of judicious scrubbing with some wet wipes cleaned the rods, followed by a light application of lithium grease (Castrol LM Grease) has made a big improvement.

After my initial assembly, the Y-axis belt met the bottom plate at quite an angle - especially when at a min/max extreme. After a bit of research, this seems to be because the design is intended for a 10mm thick bottom plate - whereas mine is only 6mm. The solution was a couple of ply offcuts to raise the height of the belt mounting point.

The standard Prusa places a nut between the Y motor bracket and the belt pulley - this seems unnecessary and causes additional strain/flex on both the motor shaft and the Y motor bracket. Removing this nut didn't take long and has not only reduced the moment on the motor/bracket, but has also given enough clearance to properly centre the Y-belt against the bottom plate.

RAMPS in the house
The RAMPS kit I ordered from xyz printers arrived yesterday - will get started on soldering that this evening...

A Mega issue
The arrival of the RAMPS kit prompted me to check that it would fit properly on the Seeeduino Mega, only to realise that I've been a complete idiot and somehow missed the fact that the Seeeduino Mega is not pin compatible with the Arduino Mega! and therefore not compatible with the RAMPS shield! :(

I did consider creating a frankenstein mating of Seeeduino and RAMPS, but then thought better of it and ordered an Arduino Mega 2560 off eBay for ~£24. It dispatched this morning, so hopefully will be here on Monday.

I'll keep hold of the Seeeduino Mega for now, as I have an upcoming project planned that will make use of the hardware...

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