Comment: With all of these 3d printers available.

(See in situ)

In reply to comment: Ooh, that one looks (see in situ)

With all of these 3d printers available.

I am still going to make my own because many have basic things wrong.

A moving build platform is one of the most obvious mistakes and only a few moved in the direction of a build platform that only moves in the Z direction. When building thin or high parts the rigorous shaking of the model will destroy it, if builds get big the mass to move will be to great to maintain speed. Only solution would be to slow it down by up to 90%, but that is not done and the results are failed prints.

Instead you should move the extruder, which has a constant weight, on the x and y axis. The slowdown needed for thin parts is only about 50%, because the plastic still needs some time to get rigid enough before the next level.
This is also not done by most and again results in failed prints.

For big builds you don't need to do anything because the Z moves only in one direction and that is also the direction gravity takes it. Currently only the makerbot replicator 2 does that.

Second obvious mistake is that the printers are build flimsy, using plastic, thin aluminum etc. This will result in a coarse finish and very often needed calibration. A rigid frame not unlike what is used with cnc is necessary and can be made pretty cheap when steel parts are used. Again only makerbot replicator 2 does that.

Third mistake is 'climate' control. Most 3d printers are open to the surroundings, this will cause differences in temperature and results in less then optimal prints. It should be enclosed and kept within a few degrees, opening a door or window in your house should not influence a print.

As prints can take several hours and very often the finest details are done the last it can ruin a print in the last minutes. Only because such easy things as rigidity, temperature control and

Unfortunately the ones that don't have these basic mistake start from around 2700US$.

I am not a makerbot fan but they are the only one that is moving to a good printer, it is not open source anymore.