El Beast - Initial design phase, comments and critique welcomed!

[Zeeflyboy]

So I've just got my hands on the extrusions...





Packaging looked okay but alas they weren't quite as well protected as one might hope - upon inspection one of the large extrusions has clearly suffered a drop on one corner.




Cleaned up with a file and it shouldn't have any impact on the final result.




To do a quick and easy check of comparative length I placed the extrusions on a piece of alucast plate and put them side by side. Given that a fingertip can detect features in the 10 micron range through dynamic touch (i.e. dragging your finger across a feature) this is actually a surprisingly accurate method of determining if there is any difference in length.






The good news is that they seem to be completely flush and more-over standing them side by side you can't even see a hint of daylight between the two, so they must be nice and straight as well.

Did the same for the smaller cross-extrusions where it's arguably much more important that they are of consistent length and the initial check seems good too. As these are shorter than the main extrusions they should be within my ability to measure using the CNC machine and a touch probe, so should be able to get some more scientific results!




Interesting to see the difference between the milled sides and the un-molested sides - you can see the gaps between the non-milled edges where they aren't flush (the edge that runs horizontal left-right in the pic)




Quick layout to see the size:




Next month's budget will go on some alu plate and some thorlabs precision corner brackets (well, and a big bbq for a new built in project I'm doing in the garden!) , and then the build of the y-axis can properly begin, hopefully with the motion components arriving some time next month too. Apart from the unfortunate corner ding, I'm very impressed with the quality. They are some seriously chunky and solid feeling hunks of alu too which is reassuring.

[A_Camera]

Nice, thank you. Care to share the supplier and the data? Maybe next time I'll buy these, since these look MUCH better than mine.

About the dent... you should complain. I received once also one with a dent, complained and without further discussion they sent me a new piece. Yes, it is just aesthetics, but it is a pity to have spend so much time and money on perfection and on something which (especially in your case) is otherwise so nicely designed and built and start off with a dent...

[Zeeflyboy]

I thought about that, and I may yet do so... The problem I'm thinking is that it really helps me out if these are perfectly matched length wise. Given that I'm sure they set the cutting length and then chopped one after the other, when done as a pair they should be pretty much spot on. If they send me a single one to replace the dinged piece then there is no guarantee that it will be as closely matched and will be subject to their cutting tolerance instead (which they don't actually seem to specify, other than allowing you to dictate product length in 0.5mm increments).

So given that consideration, along with the fact that the corner will be totally hidden once constructed, I'm leaning towards just sticking with it rather than risk extra alignment headaches by slightly mismatched lengths.

But anyway, to answer your question the profiles themselves are pre-milled pieces from misumi. The cross pieces are HFSP8-5050 (50mm square profile, milled on 2 sides - so actually 49x50mm) while the larger ones are the bulkier high rigidity GFSP8-10050 (100mm x 50mm, milled on the 100mm sides, so true dimensions are 100x49mm). Misumi have a variety of milled profiles so you can probably find one that suits what you need - the issue is actually ordering it if you don't work for/own an appropriate company as they won't sell to normal plebs like us.

[1Jumper10]

Looks very nice. I've heard good things about Misumi extrusions and they were one of the sources I had considered using in the past but I've never ordered anything from them. Thanks for the pics. They confirm my perception of Misumi's quality. Given the quality of the extrusion, do you think you really need the Thor Labs corner brackets? Looking forward to your build...

[Zeeflyboy]

There is probably an argument to be made that I could live without them...

Maybe I'll go with just a single pair at the front and see how it comes out... easy enough to add a second pair at the back if required.


On a related tangent I've been working on a custom tool drawer insert for my CNC bench... still haven't placed all tools yet as I haven't fully decided what I want to put in... also need to make the handle in the front.

[Zeeflyboy]

So as promised, something more scientific....

I used my touch probe to measure the length of the cross braces. Fairly impressive cutting tolerance really I suppose, the nominal length was 344mm and the longest was 344.34mm while the shortest was 344.28mm so they are within 0.06mm of each other. Would have been even more impressed if they were all 0.3mm shorter








So my options are to use some shim material to make them all up to an effective 344.34mm or I can try to nip them all down to 344mm on the CNC... Shimming is probably the least risk route.

[Zeeflyboy]

Got home today to find FedEx had left me a nice treat:




My linear motion stuff arrived, and initial inspections it all arrived intact. HG25 rails and carriages could probably be used for seal clubbing if one were so inclined... didn't realise quite how beasty those are.

Quality of the TBI ballscrews looks to be fantastic - finish is excellent, as is the end machining and they are as straight as an arrow with absolutely no discernible slop or play on the ballnut. I intend to do some tests with the glass scales just to see what that tells me but from a visual inspection stand point they seem top-dolla!

some linear motion porn (NSFW?)













Had a bit of an order snafu with Thorlabs - got an order receipt and they reserved funds on my bank account but the order didn't get processed. I have spoken to them and re-ordered so those should be arriving shortly. Other than that I'm just waiting on an order from motedis for various extrusion related fixings and then I should have most of what I need for the bottom frame build.