PeterE builds a 3d Printer

Gallery, Projects and General > Project Logs

<< < (6/36) > >>

nrml:
Bed movement does not seem to be an issue if you don't crank the print speed too much. Mine has the aluminium base plate, plywood insulation, MK2 heated bed, glass plate, all the clips/fittings etc and some very poorly fitting linear bearings and I still get pretty decent printouts at slow speeds (30mm/s). Rather than spending lots of time and effort in refining the Prusa, it might be better to put the money and effort into your second build after learning the lessons the first build teaches.

I am collecting the components for my next printer build, which will be an extra rigid all metal corexy printer with no printed components, a 30 X 30 X 30 cm build volume and an enclosed chamber.

picclock:
@nmrl
The one major advantage of the core xy type design is that it minimises the stepper load as the only the head moves in all axis. Clearly eliminating the issue of moving the printer bed weight and allowing higher speed/better accuracy. However the price to be paid for this is increased mechanical complexity and poorer head/bed access for maintenance/blockages or alterations. For larger machines this is clearly the way to go as the problems of moving weight around increase with size. I will be interested to see how your core xy build progresses, and what advantages accrue. Will you use V slot mechanics? I have no experience of them but it seems to be a better system than smooth rods and linear bearings. Perhaps you could do a build log and keep us all up to date.

Best Regards

picclock

nrml:
I intend do a build log once I get started. The reason I decided to go for a corexy mechanism is that it can easily be incorporated into a very rigid printer. Besides, it is a very elegant mechanism. I love the V-slot concept, but I am not sure if wear will be an issue and how rigid a gantry running on wheels can be made without binding being an issue. Also, if you are buying readymade gantry hardware the costs rise very steeply. I am planning on sticking with linear rails and oilite bushes - I have had very bad experiences with cheap linear bearings so far and Igus polymer bearings are a bit too expensive. I am going for 32 bit electronics (duet). It is going to be a challenge for me, as I don't have an engineering background, but I am sure it will be an enjoyable one.

I don't want to sidetrack Peter's thread, so I'll start a separate one in the next week or two once enough stuff arrives for me to get started. They are on the slow boat from China.

PeterE:
Just a short update. Of course my cameras battery decided to be empty, so no pictures today. :palm:

I fixed the naming to an " OK it is not an altar" level. This printer is for test and learning to begin with. The fixes went OK, but could have been much better.

This means that the portal and carrier for the X and Z axis is finally secured to the base.

All structural plastic parts are cleaned up and just waiting for assembly.

Next up is to cut the threaded and smooth rods for the Y axis motion and begin assembly, and to cut out the ply for the Y carrier. I will use the heatbed as template this first try before introducing any changes.

picclock,

Interesting things you mention about the Y axis table weight. I will weigh my setup once compiled all together, I will use a 12mm ply board instead of your alu plate. As said earlier, I also look into making a few lightening holes in the ply board as it is mainly used to carry the heatbed and glass plate.

nrml,

Interesting to read about your experiences and the way you will go for the nest build. I notice that you are very suspicious about the cheap linear LM8UU bearings, and smooth rods as a concept. On my part I have had experiences with that type of movements way back in time when I was working with packaging machinery. There was no problem with linear bearings and rods then - but I suppose they were of another quality. Will get back to that later.

When it comes to lubrication I will use the same silicon grease as I have used for my lathe and mill, namely ordinary car wheel bearing grease, good specs and copes well with both heat and speed.

As for the Z motion using M5 threaded rod, I think there is quite a difference in precision between the ordinary galvanized stuff and the stainless ones. The stainless are much nicer in both finish and movement as far as I can tell, and nearly no sloppiness either.

Will be interesting to read your build log once your bits have arrived.

No problem with side-tracking my thread.

BR

/Peter

PeterE:
OK, so a couple of pictures, whereof one i have to re-take as it got blurred :palm:

The first shows the naming (very blurred) will make a new tomorrow.

The second shows all the printed parts for the Y axis motion. Well not quite, I notice that I lack the four hold-down parts to lock the Y axis to the portal bottom. Those will come shortly.

... and finally, a couple of 8mm threaded rods in two of the corner feet for the Y axis.

I noticed when cutting them to size that stainless rods are actually quite a lot better material from both precision and stiffness point of view compared with ordinary mild steel or galvanized rods.

The small bit on the upper rod is the toothed belt tensioner in its correct position. The motor bracket is fitted in the same way on the other end. Time did not allow for all bits to come together tonight so will have to wait until tomorrow.

/Peter

Navigation

 Message Index

Go to full version