ChrisLX200's DIY Projects

[PaulB]

Hi Chris,

I can understand how worried you were, when struggling to mount the ODK to your 10 micron. That ODK looks very heavy despite having a carbon fiber tube. Those little gizmos are a work of genius.

Now all you need. Is for a clear and Moon free night to image under.

[ChrisLX200]

1 hour ago, StuartJPP said:

Hi Chris, good collection of stuff on here, really like those knobs you did...nice idea.

The 3D printer you are using, how much fettling/fiddling does it require? The reason I ask is that we have got a "proper" i.e. industrial machine at work that just does what it is intended to do with no quibbles but that cost about £10k plus the ABS is specific to the machine obviously not for hobby/home use.

I'd like to get one one day but don't want to be messing about with it too much.

Well at 5% of the cost this Wanhao 4S clearly isn't going to be as well made, nevertheless it's proven to be reliable so far. Most of the problems I get (poor prints) are user errors so I'm having to learn as I go along, yes it does need some fettling to get the best out of it, and the bed requires levelling manually (no auto-levelling here!). There are a few design gaffs but nothing that stops it working, and I don't spend hours fixing the thing it just runs and I tend to ignore it. I can honestly say this has been one of my better purchases over the years and it tends to be running 24/7 most of the time - I thought it would hardly get used when I got it ;-)

ChrisH

[ChrisLX200]

16 minutes ago, PaulB said:

Hi Chris,

I can understand how worried you were, when struggling to mount the ODK to your 10 micron. That ODK looks very heavy despite having a carbon fiber tube. Those little gizmos are a work of genius.

Now all you need. Is for a clear and Moon free night to image under.

Thanks Paul, the ODK is heavy and it has to lifted very high to get it on my mount, but the surprising problem has been accurately balancing it. I could have added a sliding weight to the OTA I suppose but I wanted to avoid adding any more weights if possible. I still haven't generated a new set of flats yet for the G4-16000 + ODK12 so I cannot process the data I already have, I must get on with that tonight. It will be clear tonight I think but a waste of time with that bright Moon!

ChrisH

[Gina]

No sign of any moon here - just thick cloud

[Davey-T]

Hi Chris, nice job, do you know how much the whole kit and cabodle weighs now ?

Still planning on getting the 1000HPS so be interested to know how the imaging capacity of them compares to real life.

Dave

[ChrisLX200]

52 minutes ago, Davey-T said:

Hi Chris, nice job, do you know how much the whole kit and cabodle weighs now ?

Still planning on getting the 1000HPS so be interested to know how the imaging capacity of them compares to real life.

Dave

Don't know exactly but I;d guess around 28-29kg all told. I don't try to move it with the camera attached (like I do with the refractor) so the heaviest lump is around 23kg. My mount handles it fine, whether my back will continue to handle it is something else....

Chris

[ChrisLX200]

I had to give up on the 3D print I was doing for the ATX PSU and start all over again ;-(.  The part just lifted off the bed completely on the LH side. This was using the laquer spray as well - that usually keeps anything stuck to the bed and the problem with that stuff is usually getting the finished print _off_ the bed! Some shapes are just more prone to warping than others I guess, and one way around it is to add 'Mouse Ears' to the corners when designing the part which offers a large surface area to help stick it down. Anyway, PLA doesn't warp as much so I'm going with that for this second attempt.

ChrisH

[Gina]

I too find some shapes more susceptible to warping, mainly large objects and ones with corners.  I've given up on that glue spray!

[StuartJPP]

The machine we use at work has single use trays which the model really sticks to (though flexes off quite easily). It first builds up a layer of dis-solvable support material which is removed from the final model. To me is very wasteful, but I suppose when you need it to work it is okay, the trays cost about £1.25 a go which isn't too much for a business to absorb I suppose.

It is these types of things that have prevented me from pursuing a 3D printer for home use, but the output of the more entry level units is surprisingly good, I am tempted. About 5 years ago they were abysmal, even the not so affordable ones and they put me off them for home use.

[ChrisLX200]

You can use printable water-soluble PVA for use as support structures on these home machines, although I've never tried (and of course you do need a dual extruder on the printer which the Wanhao has). I have not had a problem with serious warping before but this is the largest ABS print I've attempted to date. Like Gina said above, it's large with square corners, and an assymetric mass - just the thing for bringing out the worst print qualities of ABS. I've started the print again using PLA which I'm hoping will not warp.

From what I've seen of the end product my print results from the little Wanhao 4S compare well with the best of them, and you would have to pay a lot more for not much improvement (paying more money for extra convenience features really). My feeling is you would need to be paying £2k or more for something that will give you significantly better results. For my own use, objects that I would previously have hacked out of metal I find are quick to design and print off on the Wanhao, that's not to say it replaces machining metal entirely but as an extra tool it can solve some tricky design problems and avoid awkward machining setups - plus, once you have your design you can print as many as you like ;-). 

I also looked into building a printer from scratch, and I've no doubt I could do it, but for the modest cost these Chinese clones save a lot of effort even if you eventually end up re-building parts of it.

ChrisH

[fireshipjohn]

Hi, I have had good success with my printer (same as Teckydave's elsewhere here) using dilute pva glue for PLA. Not tried ABS yet.

When its comes off the bed like yours I know its time to clean and reapply some fresh PVA!

Also for designs like the one discussed here I always enable a brim to ensure its got good edge adhesion and then it's easy to break off when complete.

John

[ChrisLX200]

ABS is notorious for warping whilst PLA is usually fine. That laquer spray I mentioned earlier (it's called 3DLAC) is ordinarily very effective at holding the print onto the bed - perhaps too effective at times as the print can be very stubborn to remove. I've had a couple of situations where the print actually removed a spall of glass from the bed rather than release! (I'm on my third sheet of glass). Another tip is don't use a metal scraper or blade to remove a stubborn print, tiny scratches in the glass surface end up being a weak point for it cracking or (as above) losing a chunk out of the surface. Anyway, I've learned how to work with it, how much to use (very little), the fact the glass has to be very clean before you spray it on, and recognised you really do have to wait until the print/bed reaches a temperature <55deg C before it will let go - then it lets go with an audible Crack! and the print just pops off. It's a bad idea to use this stuff with PLA though because that doesn't contract when it cools, thus it remains firmly attached and can be a real pain to get off. For PLA I tend to use a glue stick which works well. Yes, sometimes a brim is useful but this part has a wide cross-section in contact with the bed already and it should have stuck so making contact area bigger isn't going to help I think, it's the fact I'm using ABS which is the real problem. Increasing the bed temperature might have hleped a bit too, but this part is a couple of inches high and it was the material well above the hot contact surface that contracted (it didn't lift until I was over half way through printing).

ChrisH

[Gina]

I've found that with a suitable print bed temperature ABS sticks alright to glass and releases at something like 30°C or so.  But thick objects are always a problem and I try to avoid them if possible.  That lacquer spray was a total disaster   Maybe I used it wrongly...

I've not had much success with PLA though I have had some reasonable prints.  Yes, either glue stick or diluted PVA glue seems to be good for keeping print on bed.

Currently, 3D printer development has been side-lined by other projects (clocks mostly) but that could change if the little UP Plus 2 fails.  I'm continuing to nurse it along and keep printing.

[ChrisLX200]

I'm well over half-way through the print now using PLA and no sign of this version lifting from the bed - as expected really. PLA has its uses where the object is not going to be subject to high temps but I must admit I prefer using ABS where possible.

This is incomplete warped part with the front cover, it would have been OK had it not bent ;-( It seems a waste of plastic but I'm not sure what to do with the rejects - it won't recycle where I am because it's 'rigid' plastic and they won't accept that...

ChrisH

[Gina]

A "Recycle Bot" is on my list of projects but very much on hold.  I did buy a couple of bits to test an idea or two but never got very far.  I have a a few dustbin bags of ABS ready for recycling into filament for when/if I ever make a "recycle bot".  The difficult part seems to be chopping up rejected prints into small pieces.  Fortunately (?) I have plenty of space to store material for recycling

[ChrisLX200]

As I hoped, the PLA print of the box did not warp ;-)  So the main part is now complete. I'm still waiting for delivery of banana sockets to finish the job but I may yet change the front panel as I don't really need a USB power socket on the LH side, but a SATA power socket would be useful.. This design was leeched from Thingiverse (no matter what you can think of it's likely someone has already made one and uploaded there ;-) )

ChrisH

[Gina]

Very smart Chris

[ChrisLX200]

The banana plugs & sockets turned up in the post today and I printed another front panel, Red LED indicates power is on, Green LED indicates the PSU is functioning correctly (Pwr_Ok line). This will do for the time being I think, I could add a variable voltage output + volt meter later perhaps, there's room on the LH side of the panel. Anyway, this makes good use of something that otherwise was just gathering dust on a shelf (I have several of these lying around from PCs that were updated to later version of PSU).

ChrisH

[Pan Euro]

Looks really nice.

[ChrisLX200]

After waiting over a month some plugs/sockets finally turned up in the post which I'd ordered from China. So today I did a little wiring (boring I know ;-) ). These plugs are really nice - they latch and detach very quickly, 4-pin to connect my autofocuser stepper motor to its control box. Also, I wanted to protect the wires to avoid abraision which I noted earlier.

So this (the yellow bit) is the wire protector, a small rubber grommet pressed in to provide cushioning:

The lip allows the outer cable sheath to be locked in place with a couple of cable ties:

The other end has the plug soldered on, another rubber grommet inserted in the clamp, and the end of the cable sheath etc., sealed with heatshrink tube. Made careful not of the pins because I always get mixed up otherwise!:

The socket has to go on the top of the control box - there's no room for it anywhere else - and the wires connected to the motor port on the L293D shield:

And that's it, job done :-)  The contro box has a temperature probe input (stereo jack) 5v power input (2.5mm jack) and the USB cable of course. It won't go any smaller than this using this combination of hardware, but I do have another controler using a NANO and 8255 controler (Rob's newer design) which could potentially be squeezed into a smaller box.

ChrisH

[PaulB]

Very nice Chris,

Now all we need is a clear sky?

[Horwig]

1 hour ago, PaulB said:

Now all we need is a clear sky?

I remember them, but I have a recollection I was in short trousers then.

 

H

[ChrisLX200]

I did get chance to use it Thursday night, first time for weeks... It was not a dedicated imaging session though because I still have issues to work through. Got some luminance data on a couple of galaxies though (M51 and ngc3521)

ChrisH

[ChrisLX200]

I just realised when I went back to check my order for those 4-pin connectors that the ones in my posession are actually 12mm fitting - I ordered 8mm. I can't be bothered sending these back to Hong Kong, not given the shipping times. They do the job certainly but not as discretely as the smaller versions would have. MAybe I'll order some more... but try an email first to check the specs haven't changed. They're described as 8mm Panel Mounting Self Lock 4Pin Metal Aviation Connector Plug ( http://www.ebay.co.uk/itm/121779262048?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT ). 

I made a little video showing how they lock in place ;-)

ChrisH

[Gina]

They look nice   I think the 12mm size may be better - easier to solder wires to.