New to 3D Printing - Need guidance on modeling technique

[fcorona76]

Good morning!

As the title states, I'm new to 3D printing. I've been in design and engineering for 25 years and have most of that experience in plastic injection molding, die casting and steel forging. I'm more than familiar with solid and surface modeling and what it takes to make production tools for any of those methods so I'm hoping the transition to 3D printing at home goes pretty smooth. I just bought a new Monoprice Maker Select printer for home use and got it set up in a flash. It seems that they did a test print before shipping as there was a PLA butterfly already attached to the print bed when I unpacked it....as well as a jammed nozzle. I got it cleaned out and had my own test print going in about 25 minutes time. It all turned out well but now I've got some questions on how I need to model my own designs to use for this printer.

Two things stood out to me that I'm not familiar with how they work and I'm not sure of the terminology so I don't know what to search for:

1) The sample that I printed was a small elephant that was hollowed out and had a lattice structure to internally support the exterior walls. Is this type of structure done in the slicer program (Cura) on a water tight part or is it something I have to model in manually? I believe its referred to as "in-fill" so if it is I can read up more on that.

2) Both samples also had a small .030-.040" thick bed printed out that was meant to be snapped off upon finishing. It consisted of a tight crossing lattice pattern of very thin layers. I'm assuming this is done to allow removal from the print plate with minimal damage to actual part and reduce the actual surface area of material that is in contact with the plate (again to make it easier to remove). I've searched high, and low, but I'm not finding any information on this type of feature either. Again, is this something done automatically in the slicer or is it modeled directly? If modeled directly, what size should I use for the layers and lines?


Thanks for any input you can offer. I'm looking forward to throwing some of my own projects at this by the weeks end.


Frank

[curious aardvark]

Yep the infill is generated by the slicer.
It's pretty neat. basically you model everything as a solid and you can vary the skin thickness (layers and outlines0 and density and pattern of the infill.

So to make a hollow item just use 0% infill and at least 3 layers and outlines. Layers are usually considered top and bottom and outlines the sides.

Unless I need extra strength or flexibility my standard settings are 3 outlines and 3 top and bottom layers with 15% infill.
You can vary the pattern of the internal fill matrix to give different strengths in different directions.

The flat thing is called a 'raft'. It's there to give a flat 'sticky' surface for the print.
Once you have the printer dialled in you should not need a raft. Pla - particularly should not require a raft.
Your printer is actually a wanhao duplicator i3 mk 2.1 - So if you want to make any modifications - that's the one to search for, particularly on thingiverse.

Given that you have a heated build platform I would also Highly recommend a sheet of printbite to print on.
Removes all necessity for glue or tape or scrapers. Basicallly stuff sticks to it when it's hot and detaches when it's cool - or with a sharp tap from a hammer.
My thread on it: http://3dprintboard.com/showthread.p...-surface/page3

Failing that cheap pva gluesticks seem to offer the best alternative.

If you fancy trying flexible prints - read this thread: http://3dprintboard.com/showthread.p...n-instructions

In fact read it anyway - lots of useful info in there :-)

[fcorona76]

Thank you. Hard to search for something when you dont know the term to search for. I'll keep on reading and I'm sure I'll be back to post up on things I'm making.

[curious aardvark]

Look forward to it :-)