New guy curious about Printing Costs

Good morning everyone,

New to the world of RapRep. Just trying to get a feel for material costs and production time.

Been desktop CNC’ing for 3 years with a Roland MDX-15 and have 10+ years experience with programs like 3DS Max and Rhino.

So say as a hobbyist I just purchased a Mendel with a .35mm nozzle.

And I have purchased a 5 pounds of 3mm ABS filament for $58 USD.

What is the volume of this plastic?
Without even thinking about production time based on nozzle size if I knew the price per CC of filament I could just punch in a scale size of a design in rhino and find out it’s volume and say it’s going to cost me X to make.

Next, how much can an extruder extrude based on nozzle size over time?

I’m sure intricate Eiffel tower model that has the same volume as a solid cube might take longer to build, but I’m just trying to get a basic rule of thumb.

Was hoping to find a mini spreadsheet that would explain these sort of numbers to me.

Thanks for any info,

Michael

Michael

Sorry I cannot help with your materials calculations, but I would like to point out that it is very rare that we print anything with a solid inside.

I have not printed much, but excluding the shels of my objects (usually about 3 layers) the infill is around 20% or 30% (or 80% to 70% hollow).

So you would need to decide how solid you wish your objects to be.

Regards

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What is the volume of this plastic?

ABS's density is 1.04 grams per cubic centimeter.
Read more: [wiki.answers.com]

5 lb ABS x 1 kg / 2.2 lb x 1000 g / 1 kg / 1.04 g / cc = 2185.315 cc.

Quote

Next, how much can an extruder extrude based on nozzle size over time?

Depends on how fast you can extrude it!

Seriously, it is just a simple volume calculation based on your set layer height. Generally you can always obtain a layer height of ~75% (or 80%) of the hole size so you must simply calculate the volume of your cylinder extruded in 1 second for 0.75 x hole size based on your speed. Use a spreadsheet and have speeds of between 20 and 60 in steps of 5 and then you have your answer (based on your speed which is dependent on your extruder capabilities).

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

As an afterthought why don't you simply install Skeinforge and run some of your models through (generally 20% fill is more than enough for very sturdy objects). It will tell you how many cc are required for the model.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Hi Michael,

Just to elaborate on Bob's answer (I wrote this without noticing the updates already written, d'oh!) ....

Skeinforge (the program that converts your 3D model to instructions for the mendel) has a module called "statistic". You set the parameters you need (filament size, layer height, etc), create the corresponding gcode file, and if the statistics module is turned on you get a rundown of the time, volumes and so on. If I saw it correctly it even had a $ amount in the latest version - but I don't know how it calculates this (probably a setting somewhere)

It may be worth your while playing around with it to get a feel for times and volumes etc.

Hope it helps,
Gary

Thank you so much for the feedback.

You sir are awesome. This is precisely what I was looking for.

Thanks again rhmorrison and garyhodgson. I wouldn't have tried Skeinforge unless someone mentioned it.

Oddly enough I was using Roland's software to do calculations on milling toolpaths in the same theme as what you suggested with Skeinforge.