Simplify3D printing part of first layer too fast

[dramsey]

I'm trying to print a simple key ford design I downloaded from Thingiverse. The key fob is an oval, with a bulge at one end for the hole for a key ring.

Simplify3D's default settings are to print the first layer-- this is Makergear PLA, BTW-- at 50% speed. When I start the print, it prints a small skirt for the key fob hole, and draws the rim of the hole as the first layer. That goes fine.

Then it ramps up to full speed and tries to draw the much larger oval comprising the rest of the key fob. That doesn't work-- the filament doesn't stick and is dragged all over the bed.

It seems (judging from the skirt that's only drawn around the key fob hole area, and not the entire model) that Simplify3D "thinks" the first layer only comprises the key fob hole.

Is this just a poorly constructed model I'll have to replace?

[Jules]

It's possible that the first layer is just around the keyhole. (Know how they sometimes have a little raised rim around them?)

One way to check in S3D is to slide the scrubber all the way back to the first layer and see how it looks on the Preview. If the bottom layer only appears around the hole - that's the answer.

(If that's not it....try clicking on Edit > Drop Model to Table in S3D.)

[dramsey]

Well, after beating my head against this for a couple of hours, the answer is: the "customizer" on Thingiverse produces crappy models. My solution: design my own from scratch in Sketchup.

(And yes, I did confirm that the ring hole is the first layer using Simplify3Ds preview mode. GOD I love that feature! It's also invaluable for checking your own models.)

[wmgeorge]

FYI a lot of stuff on ThingVerse may not print right, they look good but unless some others have successfully printed I would suspect a poorly designed model.

[willnewton]

Go to edit menu and select "place surface on bed" and click on the large flat that is supposed to be the base. Now it will make the flat parallel to the bed and bypass the bulge.

Also, you can double click the model and in the Change Position fields, select Z-offset to enter a negative number. That will "sink" the model into the bed and get you to a flat surface. If your layer height is 0.25mm and it just prints the bulge on layer one, then set it to -0.25mm.

Use your preview window to verify the results and click "layer by layer" to see what is being printed and where.

There are some models on Thingiverse that make you say "Why? Why? Why did you do that?!??!?!?!"

Unfortunately, if the model has a raised lip the "Drop model on Table" will not work in that case (Sorry Jules!). As it will just sit the model down on the raised part.

And just in case, having not seen the model at all. Are you printing it upside down? I just had the odd thought that it may look flat on both sides, but one side has a ridge and the other doesn't and it's a small detail that could be overlooked and I had it happen before and you know just asking because, "Hey, it happens!"

[Jules]

.....Unfortunately, if the model has a raised lip the "Drop model on Table" will not work in that case (Sorry Jules!).

Hey, I saw that remark!

(But, but, but .....in my defense, i told him to drop it on the table if it did not have a lip on the hole.)

[dramsey]

I am replying to you guys, honest. It just seems to take a long time to get my replies approved. Is there some metric that must be passed to be able to post messages without moderation?

[dramsey]

BTW, your suggestion to sink the model into the bed a layer or so (I didn't know S3D could do that!) completely fixes the problem-- at least in Preview. Thanks! I'll be trying it out today.

[Jules]

Yeah, everyone's first few posts are moderated. (Cuts down on spam.)

[dramsey]

Hm. I'd think spending upwards of $2K with Makergear would buy one some sort of indulgence. Oh well!

I did try printing out the key fob after adjusting the model Z offset trick, virtually sinking it slightly into the printer bed. Worked great! Now to print 'em 8 at a time...I need about 300.