Mostly 3d printed EQ5/HEQ5 class mount progress thread ...

[vlaiv]

2 minutes ago, Elp said:

you could repair that split with it

You are quite right - I could also try to chemically weld it - but I guess that would make even more mess than using soldering iron.

However, given the location and extent of "damage" - I'm just not going to do anything about it. Point of that little bit is to hold one of 4 trusses securely - to create friction so it does not easily slide out of the hole. As is - it has more than enough friction on it. In fact - even if I did not use bolts to tighten it there was plenty of friction (enough to work up a sweat while trying to put the whole thing together ).

This is prototype after all. I'm not sure I'll be using it like a regular mount as is. It will serve a purpose to test everything - and when I'm finished with that, I might "rebuild" it to a working mount after all - by replacing all the bits that I end up redesigning.

[Vroobel]

1 hour ago, vlaiv said:

It is actually fairly cheap if you print it your self. I'm not sure how much it would cost to have all the parts printed for you by 3d printing service though.

I've spent roughly 100 euro on plastics so far (4 spools at ~25 euro each), might need one more spool.  Aluminum profiles were less than 25 euros (for total of 25 euros I purchased all that and also tube for DIY small 80mm refractor that I'm building). Stepper motors are like 10-15 euro each and we need two, Raspberry PI pico is something like 5-10euro and drivers are 10 euro each. Assorted pieces of hardware are less than 50 euro in total (I'm just eyeballing it).

I believe that bill of material will be around 250 euro if you go with ASA or possibly around 350 euro mark if you decide to use stronger filament like Prusa PC Blend (which has very similar properties to ASA as far as durability / absence of creep goes but is at least double the strength and more stiff - but costs twice as much).

Again guessing, but total with external printing service might set you back 500 euro or so? Still much cheaper than commercially available options in this class.

 

I'll try to copy it in future (of course, if you decide to share it) using the Prusa PC Blend, just for fun, but first thing is to buy a Prusa printer with dedicated cage. Not because of fumes (Styrene-free (non-toxic compared to ASA)), just because of the temperature requirement. Thanks for the info about this filament, I didn't know it. 

Edited June 10 by Vroobel

[Vroobel]

1 hour ago, Elp said:

Having a set of files at hand is useful too, filament files down quite well. It was useful when I made a model cast tool with removable tool inserts and sliding ejection system.

You can get hot tools too I've got one for punching holes, carving etc (it's a bit like a soldering iron with different tip attachments), you could repair that split with it. Its a messy process though as the melted filament tends to stick to the tool you're using (a bit like trying to carve hot melted chocolate).

I use a quick bonding epoxy resin to fix splits like this. I think it's less messy. 

[vlaiv]

50 minutes ago, Vroobel said:

first thing is to buy a Prusa printer with dedicated cage

Look into this printer:

https://www.3djake.com/qidi-tech/x-plus-3

(there is max version as well - with larger build volume and higher price tag).

It's not as polished as some other printers - but it's fully enclosed and comes with chamber heater to be able to hit 65C inside.

(however, do research on it, if I remember correctly, there has been some issues like heater fins being live with 220V if power plug is oriented one of two ways - while you can't easily access those fins and you would not touch them because they are hot - it is still large safety hazard. Might have been corrected by now).

I'm just mentioning that printer because of heated chamber. PC Blend will warp if not properly thermally managed when printing large parts. There is also carbon fiber version that is even stronger and prints very nicely - but suffers from somewhat lower layer adhesion (as most CF filaments do).

 

[Vroobel]

Thanks for that. I would consider the QIDI Max3 though it's not as big printing surface as I thought about for one purpose related to a kind of business. 

Edited June 10 by Vroobel

[vlaiv]

Issue resolved.

It turns out that lowering gap from 1mm to 0.6mm and increasing diameter from 15mm to 15.2mm solves all the issues.

Aluminum pipes can now be very easily inserted (but are not loose) and tightening the screw really tight - just closes the gap. In fact - when the gap closes, pipe can't be moved any more and tightening the screw becomes very very hard (I did not want to force it crazy - bit might do just to test it out).

Ok, just tried it - tightened it as far as it will go and it seems fine.

[vlaiv]

Progress update ... (sorry about poor focus).

I cheated a bit in that image. Counterweight shaft is just shoved in its place - it's not secure. I need to do some drilling and m8 tapping to get it to screw in properly into the mount and be secure.

I cut 40mm x 20mm x 8mm aluminum stock that I'm going to drill in center and tap with m8 thread. Since I don't own drill press - I'm going to 3d print a drilling guide for that so I can be on center. Similarly, I'm going to drill and tap m8 into shaft itself (again, it's going to be done with 3d printed jig of some kind - I have an idea of how to best do it).

Then I'm going to cut small piece of M8 threaded rod that I'm going to epoxy in the shaft (put some 2 component epoxy and screw it in tight) and I'm going to epoxy custom "nut" into designed space in 3d printed part. That should form secure connection that can be disassembled if needed.

Next steps are to finish CW shaft and get some counter weights and to 3d print (I'm going probably need another spool of filament unless I do it in red color) dovetail clamp and adapter.

Then I'll test setup with 4" F/10 refractor - just basic balance and how it "feels" and then I'll move on to design and print reduction and motor housing for the mount.

[Vulisha]

Just advice on controller, not sure are you awarw of its existence, but I think OnStep is a grear thing to go for as a controller, it is well supported, open source, and full of features.

You can start with fystecE4 for ~35eur, that has drivers already installed, tmc2209.