What are BOM changes for 500mm extrusion Prism 1.5?

Hi,

After looking a various options I'm planning to make a Mendel Prism 1.5. I've already built a Sells Mendel.

I'd like to build it with a larger print area using 500mm extrusions. However, I'm unsure of the knock-on effects to other components.

Here's the one's I've identified:

- Smooth rods - These now need to be 10mm not 8mm but what are the new X, Y & Z lengths?
- The BOM says I need 2 40mm M8 cap screws (plus nuts). Would that become M10 cap screws & nuts?
- Do the 12 LM8UU bearings become LM10UU?
- Do the 2 608ZZ bearings become 10mm versions (LM10zz????)

Is anything else affected that I should be thinking about?
(obviously the print bed itself nees to be bigger & I'll need to sort something for the heated bed)

All help gratefully recieved

Thanks

Pete

Yes they make LM10UU's but the 608 are not used on the 8mm rods so are not changed.
I would guess 550mm for the y-axis and z-axis rods (and cut them down to suit) and probably about 800 for the x-axis.
The y-axis rods logically should be 500mm plus a but more so 550mm should be a good guess.
The safe way would be to measure the rods after you have built the frame
You will need to find or design your own 10mm x and y carriages. There are 10mm x-ends on Thingiverse so someone might have done the carriages by now.

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Richmond, New Zealand
Thingiverse ~ YouTube

Well,

I haven't worked up a BOM for the Prism 1.5 as of yet. I really need to get on that. And I need to build a 400mm version to finish where I left on in the build instructions. So much to do...so little time.

For a machine using 500mm extrusions the smooth rod lengths are as follows:

X-axis: 605mm (you can get away with 600mm)
Y-axis: 540mm
Z-axis: 480mm

The 608 bearings remain the same as they are for the X and Y axis belts - the supporting M8 hardware remains.

The biggest choice you have to make is whether to use LMxUU bearings or sintered bronze ones. Personally I prefer the sintered bronze bushings. I have a new version of the X-ends that are highly configurable. They can accept either style of bearing, and can also be spec'd out for any size leadscrew. I don't yet have a version that accepts delrin nuts - they are fairly expensive. Currently I'm running with 1/4" ACME leadscrews using the standard 2 nuts and a spring per axis to remove any backlash.

But I think the biggest thing at this point is that for this size machine you *must* use 10mm smooth rods on all the axes, even the Z. The X and the Y are necessary for the spans involved. The over sized Z helps reduce/eliminate Z-wobble.

May 500mm extrusion machine:


Any questions don't hesitate to ask.

But a basic BOM:
(10) HFS5-2020-xxx extrusions
(100) HNTA5-4
(100) M4x14
(100) M4 Flat washers
(100) M4 lock washers
(~40) M3x20
(~25) M3x10
(~25)M3 Nuts
(~25) M3 Washers
(5) M10x1m smooth rods
(5) stepper motors
(2) pulleys, preferably GT2-36 and accompanying belts (2@1200mm)
(12) bearings (LM10UU/10mm press bearings/some combination of the two)
(2) leadscrews, 400mm each
(4) nuts for leadscrews
(2) springs to fit leadscrews

But this BOM doesn't include the Y-axis single-point attachment component or the X-carriage or the extruder.

I'll get a full BOM worked up this weekend.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

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