Walls not solid

Hi everyone!
I have Black FlashForge Dual 3d printer!
I seem to have overcome most issues by reading all of the posts on this web site.
I have the left hand extruder up out of the way, I use blue 3m tape, and hairspray .
No curling due to raising the bed temperature, no coming undone, and no scraping.
I use ABS White which came with the machine this has nearly run out, and will need replacing.
My problem is I model 1/76 scale model Fairground vehicles! And am trying to replace the original body with a printed one.
It is an open body with raised sides for the artwork on the outside, there will be two resin generators on the flatbed part of the body.
I use Google Sketchup to do the drawings and save as an stl file.
The problem comes when printing the sides have a flat edge all around the back and on both sides, the thickness is 2mm but when you look down onto the top edge there are two walls which have not been made solid.
The sketchup version I use is the latest free version, and does not do solid items.
When you remove a part of the drawing you can look inside, and it is not solid.
I have used all settings infil and shells set to 100% and tried different build thickness's but it makes no difference!
As anyone got any ideas.
Regards
John Williams

ps can you recommend which white abs I should buy when this runs out?

Hi John,

The type of white ABS is a gamble, some are a nice white and some are off white, you just have to find a good supplier. Ebay is the best for me, and I pay on average about $22-$25 per roll with free shipping.

The lack of sealing or joining on the tops walls is a replicatorG issue, are you printing with RepG?

It happened to me alot, so I switched long ago to Makerware to solve that issue and I pretty much use that to print now as it does a much better job of the top and bottom layers.

Hi Geoff
i tried the replicter software, and after reading what you said about Makerware, I down loaded it and have used it more or less from the start.
the problem seems to be worse if I increase the width of the side panel.
the item I'm trying to get right is a three sided body for a truck.
its about 35mm wide by 33mm long by 18mm tall, and 2mm thick.
the drawing looks okay but has it is not solid I assumed increasing the infill to 100% would fill in the gaps.
i was wondering if it's to do with the slicing, ie not seeing it all.
or the travell speed when printing!
Regards
John

Hey John,

If the gap is too thin it will fail to infill, so what you are better off doing in your scenario is adding more shells, in your case I would recommend 3 shells. The shells print from the inside to outside perimeter, and also adds more layers to the top and bottom layer (i.e you say 3 shells, that means vertical and horizontal layers in makerware, it has no differential..) so it will do 3 layers for the bottom, sides and top, making it a very solid piece with no gaps on the top of the thin walls.

I print everything now with minimum 2 shells, it's just habit and it pays off.

how have you processed the sketchup files to make them manifold/solid ?

Quote:

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Originally Posted by curious aardvark

how have you processed the sketchup files to make them manifold/solid ?

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I'm not sure what you mean by manifold or solid.
however the free edition of sketchup does not allow you to build solid walls, so assuming manifold means not solid then yes they are processed manifold, they are saved as an stl file then for use on the makerbot software.
regards
john
in the UK