First 3D print

[simond]

You’re using Chitubox, and the basic program has a “detect islands” button, top left on one of the screens.

It takes a few minutes. I do it for each piece in turn. Once you’ve detected the islands, you can scroll through the model layer by layer (there’s a “jump to“ function which helps) to understand what’s not properly supported.

You absolutely need to do that. It will highlight unsupported bits of your model, these must be fixed, by getting the orientation and supports right. Choose the orientation to minimise dustortion, or to avoid supports on visible faces, then sort out supports, to ensure you have no islands. It takes ages on complicated parts, but it is a key step in the printing process.

If you don’t do that, no amount of luck will help!

An aside. The parallel part of your clock support might be easier as a bit of K&S brass tube. The cast detail bits can be printed, and just slide on. Of course, that’s not going to work if it’s tapered..

 

[Kev T]

Great stuff thanks folks.

 

[J_F_S]

I am a newcomer to this game and have only completed four sets of prints BUT (kiss of death spoiler ...) they did all work perfectly and they amount to 1.5l of resin!! I therfore offer my experience NOT as an expert, but as someone trying to take baby steps like yourself.

To add to what others have said, I venture to suggest that you have not quite got the idea of how supports work and what is needed. There are plenty of Youseless Youtubes out there, but this one I found helpful ...

I see you use 60% support density, but personally a have not used less than 75% - cleaning up supports is a pain but a failed print risks damaging your FEP or even your LCD screen. So play safe - add far too many, then add a few more ... - when I am a lot more confident I might dial back my support density! Although my parts built well, there are distortions on the lowest edge from which I built - so although I used a lot of supports, I now know that even more were needed to support the first 20 or so layers of the print. I did not use a raft, but did add extra supports to ensure there was plenty of area to resist the build pressure and carry the weight. With such large objects (covering almost 75% of the build plate) , I was concerned that a raft would risk too high a suction force - by using supports, you can leave small gaps here and there between their "feet" to break the suction. The opposite might be true for small components.

Not suggesting this for you, but personally, I have started - not with models but - with larger geometrically shaped-objects (they are actually tooling and jigs for a full-sized job) that way I can assess what distortions / geometric flaws emerge and then make any necessary calibrations to the printer.
And use an easy resin - I used Siraya Tech Build - being transparent to UV it post-cures very well - even on thicj sections like mine.FAR too

Hope that helps!

Best Wishes,
Howard

 

[Kev T]

Howard
thanks for the info, very useful.
I've been having problems with Chitubox crashing on my MacBook, so after a bit of research I've downloaded Lychee and setup a print using that slicer. Let's see how that goes.
Kev

 

[simond]

Kev

herewith the "detect islands" button



Next to it is a "delete islands" button, which you can use to eliminate the odd voxel, but generally, you would alter the orientation or supports to support all the overhangs.

I seem to have been lucky with the first model, the solebars had a single island



The lower button above the slider on the right selects "layer with island" and then you can use the down-arrow to jump to each layer in turn.



There is a very faint red line to the right of the slider, that is the layer with an island (there was only one) and I now need to find it in the slice on the left.

Found it - it is the buckle on one of the leaf springs - the red rectangle



I was able to fix that with a couple of extra "legs".

There were a couple of zones, on the inside of holes, where it decides, for whatever reason, that they are islands - they can't be - so those, I do delete. I ended up with 7 layers with repetitive "faults which weren't" and simply deleted them after the final slice.

And then, bit by bit, until I got here;



and this is going to the printer, and I'm going to bed!

It's saying a couple of hours - I think it will be a bit longer, but it'll have plenty of time to drip before I take it out tomorrow. I'll be washing it whilst feeding the cat and it'll be cured during breakfast. I'll only get to play when I get home from the office.

hope this is helpful
Simon

 

[Kev T]

Thanks Simon very helpful
I had a go but it crashed again part way through . I'm pretty sure I'll give up with Chitubox. I suspect that my 8 year old MacBook pro is a bit underpowered, although Fusion360 runs fine.
So far Lychee is OK so I'll try a more complex print with that.
Kev

 

[simond]

glad it was useful.

Chitubox does appear to be a bit power-hungry. That is why I do each component in turn, so it only supports and slices one at a time. The island detection does seem to need lots of memory. I'm using a two-year old Dell GS15 but only have 8 gig of memory - it takes a while to do the detection and the memory usage is well up in the 90% range. I should splash out as the laptop is otherwise brilliant.

The print worked as expected, but there are some issues on a couple of components, I'll put something up on my workbench thread this evening.

 

[Kev T]

I managed to get a print with some success. The problem I had was too many supports meaning some of the prints were damaged when I attempted to remove them. Looking at the supports they merged into a blob in some locations where they were close together. Online info suggests that this may be temperature related as the resin isn't flowing as it should.
Online info also suggests that getting the correct temperature can be critical in successful printing so I'm going to build a heater of some sort.
I've got too little room to run a couple of reptile heater pads, and again too little room for most of the PTC ceramic heater and fans assemblies. However I've found a print that fastens to the top of the Z axis column which I'll give a try.

https://thangs.com/designer/viperx85/3d-model/Mars3%20Enclosure%20Heater.stl-38045

the heater is £12ish and the controller £10ish. I already have a suitable psu. I'll try the heater wired to 50W to see if that's enough.
These and many many iterations of this type of heater are what is described as constant temperature heaters. They are PTC which stands for positive temperature coefficient. This means that as the temperature of the heater rises the resistance rises and self limits the max temperature.
Kev