Pat Sparks BOMARC Build

[LSP_Kevin]

1 hour ago, airscale said:

what slicer software are you using Kev? and are you using the auto nsupport feature or adding them yourself?

 

I generally find with chitubox, giving the part about a 35 degree angle and using auto supports is about 95% successful

 

you can always go in and edit auto supports where they hit the work or are oddly placed

 

That's pretty much what I've been doing, though the preferred angle on my machine is 45° (50 micron layer height at 50 micron resolution). For the tail section of this project (which I'll post about later), I did all the supports manually, which was the first time I've done this. Oddly, though Chitubox won't let me change the weight of any pre-existing supports, only move them around. If I want to convert a 'heavy' support to a 'light' one, I have to remove it and re-add it.

 

Kev

[LSP_Kevin]

OK, here's the latest update. Even though the last print wasn't perfect, it's good enough for my purposes, and I've decided to move on to the next section - in this case, the tail. I took what I've learned from trying to print the centre wing section, and applied it to the tail, which is similar in layout:

 

 

For the first time in my journey with 3D printing, I went full manual supports on this one, and was pretty confident that I'd covered all my bases. And I was quite optimistic when I pulled the print out of the printer 7 hours later:

 

 

 

It was only when I removed all the supports that I discovered that I'd missed a spot:

 

 

So close!

 

More experienced practitioners are telling me to print shapes like this in a leading-edge down orientation, so I might listen to the voices of experience and try that next. With any luck, I'll nail this in two tries! Otherwise, it's more of this:

 

 

Kev

[Hagar]

Looking very interesting still. You might already know, but if you dip the part in hot water (not boiling) before removing the supports they come off very easily and barely leave a mark. This is before curing of course. As some parts are hard to position when curing I have been using some pyrex beakers to hold the part with great success. Looking forward to more.

James

[LSP_Kevin]

7 hours ago, Hagar said:

Looking very interesting still. You might already know, but if you dip the part in hot water (not boiling) before removing the supports they come off very easily and barely leave a mark. This is before curing of course. As some parts are hard to position when curing I have been using some pyrex beakers to hold the part with great success. Looking forward to more.

James

 

I generally use a hair dryer for this task, as it's quicker and far less messy - and cleaning up resin 3D prints is messy enough as it is!

 

As it happens, my second print of the tail piece failed for reasons I haven't had a chance to investigate yet (it's still hanging off the build plate). But I'm guessing it's lack of supports again. And I thought I'd nailed it!

 

Kev

[monthebiff]

This is proper interesting stuff Kev! This 3D printing thing seems pretty difficult to get right but I guess once you have found the magic key the world is your oyster.

 

Regards. Andy 

[LSP_Kevin]

1 minute ago, monthebiff said:

This is proper interesting stuff Kev! This 3D printing thing seems pretty difficult to get right but I guess once you have found the magic key the world is your oyster.

 

Regards. Andy 

 

It's learning to do the manual supports successfully that I'm finding the most difficult part. I thought I'd nailed them with this latest print, but as we'll see when I post the photos, I most certainly did not!

 

Kev

[waxdart]

Ha Kevin, Your desktop of resin casualities looks like mine. "I see dead prints" However, I am learning from each one.

 

Tim

[LSP_Kevin]

9 minutes ago, waxdart said:

Ha Kevin, Your desktop of resin casualities looks like mine. "I see dead prints" However, I am learning from each one.

 

Tim

 

That's my goal too, hence my rather cavalier approach to wastage!

 

Kev

[LSP_Kevin]

So, here's the promised update about the latest print. With deep urging from expert friends, I tried a nose-down orientation for the tail section this time, and while I personally thought I'd nailed the supports, the results said otherwise:

 

 

 

 

This nose-down orientation has me a bit mystified in terms of how best to support it. Several of the supports under the tailplane failed - possibly due to being too long, and standalone, rather than scaffolded with other supports. All I can do is try again with more supports!

 

Kev

[Landrotten Highlander]

I think a shallower printing angle might help.  uncured resin is rather weak when it comes to self-supporting its weight, so the very thin (unsupported) tips of the control surfaces will 'float' in the resin bath, hence the upward bend.

 

A shallower angle, combined with supports near the tip will prevent this from happening, as the supports will 'pull' the tip into position, while the slightly wider printed wurface fo this thin layer will help in withstanding the upward pressure of the liquid resin on the semi-solid resin.

Edited July 21, 2023 by Landrotten Highlander

[Dandiego]

Kev, I am no expert, of that I am certain, but I always use the automatic supports generated by the slicer. I have not had a perfect record when doing prints, but 95% I would say.

 

Dan

[geedubelyer]

Although this is taking you a few attempts and using alot of resin it is a fascinating process to observe.

The wings appear separate to the fuselage in your latest image. Forgive my ignorance but is there a reason why you are printing them in situ?

If you printed them as stand alone items might you have better success?

[LSP_Kevin]

2 hours ago, geedubelyer said:

Although this is taking you a few attempts and using alot of resin it is a fascinating process to observe.

The wings appear separate to the fuselage in your latest image. Forgive my ignorance but is there a reason why you are printing them in situ?

If you printed them as stand alone items might you have better success?

 

They're not completely separate, being joined at two spots - one is the mechanical pivot point on the real machine, and the other is a tab that Pat designed in for printing stability. The reason I'm printing these sections as whole units is to see if I can, and because my last attempt at printing them separately didn't go too well. I'd also prefer to have the fewest number of parts for assembly purposes.

 

However, my third attempt at this tail section just finished printing, and while it's a whole lot better than the previous effort, it was still a technical failure. I'll post the photos in my next update. For my fourth (and probably final) attempt, I'm going to take Ben Schumacher's suggestion of printing it vertically, nose down. If that doesn't work, I will indeed be printing the tip sections separately (as Pat has kindly provided them as separate files also), and using them to replace the failed ones on #3.

 

Stay tuned!

 

Kev

[LSP_Kevin]

So, here's the latest in my Daily Fail series:

 

 

This one was pretty close, actually, with the most obvious defect being the massive shifting of the forward top of the fin. In the photo below, you can also clearly see the layering effect across the shallow curve of the fin:

 

 

Less obviously, neither probe printed properly. I also keep getting this annoying undulating effect on the surface closest to the build plate:

 

 

Not enough supports, I suppose - which seems to be the cause of all my 3D printing ills right now! Next try will be a vertical print, nose down. If that doesn't work, I'll cobble a finished piece together from what I've done so far. If I need to, I can reprint the outer fin and tailplane parts separately.

 

Kev

[LSP_Kevin]

Allow me to present ... BATMARC!

 

 

Kev