Only the surfaces that form a closed object can be 3D printed. The closed surface model has to be converted into a solid object, which is described by the .STL file.
We have two kinds of 3D powder printers - the Z510 and the Z310. The following are the differences between the two printers.
Z510 - x10 x y14 x z8 inch / 254 x 356 x 203 mm
Z310 - x8 x y10 x z8 inch / 203 x 254 x 203 mm
Z510 - can print in full 24 bit color
Z310 - only print parts in monochrome
Because the Z510 uses a finer powder it has a better resolution when compared to Z310.
Parts coming out of Z510 have a greater initial strength. If given sufficient time to cure parts printed in Z310 will also achieve same strength. But because of the grater initial strength it is advisable to print fragile and thin parts in 510 to avoid breakage
Z510 - $3.50 per cubic inch
Z310 - $3.00 per cubic inch
First, the 3D Printer spreads a thin layer of powder. Second, an ink-jet print head prints a binder in the cross-section of the part being created. The build piston then drops down, making room for the next layer, and the process is repeated. Once the part is finished, it is covered with loose powder, which is then shaken loose from the finished part.
If the file is submitted as .zbd then there would be no confusion as far as scale of the parts is concerned. In the past we have had problems with the scale more than once, when we have processed the file in different units then what the student actually wanted.
You can see how it is going to actually get printed, by slicing the part layer by layer
You can look for grey areas in the part by yourself and fix them. Grey areas are due to non agreeing normals (and if all the normals are not pointing outwards) and they don't get printed.

You can have the part at the desired orientation, because there is a possibility of deformation in the part if they are not oriented in a correct way. Hence you can orient the part as you want.
You can calculate the price by yourself and if you want to pay less for the part you can remodel the part (by shelling, reducing the size etc.). Pricing procedure
If we have .zbd's from students then it saves enormous amount of time and man power which eventually will benefit the students because we can get more projects done.
Comments