Review: Printrbot Assembled Simple Metal

Hackaday is getting back into the swing of doing reviews, and with that comes reviews of the tool du jour, 3D printers. I have some reservations about reviewing a 3D printer; they’re a new technology, and what may be standard today could be hopelessly outdated in a few months time. Remember geared extruders? The new hotness is, apparently, direct drive extruders.

This is a review of the Printrbot Assembled Simple Metal. If you need any evidence that reviews of 3D printers have a shelf life, you only need to look at the Getting Started guides for this printer. When I bought my Simple Metal, the Printrbot recommended software stack was Slic3r and Repetier-Host. Barely three months later, Cura is now the Printrbot recommended software stack. If you think a simple change in software is inconsequential, check out these prints:

prusa parts
Prusa i3 X-carriages. Left sliced by Slic3r, right sliced by Cura

The print on the left was sliced with Slic3r. The print on the right was sliced with Cura. Notice the small teeth that grip the timing belt on each of these prints. With the Cura-sliced print, everything is fine. The Slic3r-sliced print is a complete failure, not of the machine, but the recommended software for the machine.

Therefore, if the goal of writing a review is to have a definitive opinion of a piece of equipment, a number of questions must be addressed. Since most 3D printing software is open source, should software be included in the review? Is the value proposition of a 3D printer simply a function of price to build volume (this seems to be the standard metric now), or are there intangibles? Should the review cover the quality of prints out of the box, or should the review only focus on print quality after dozens of hours of tweaking? I simply don’t know the answers to these questions, and I suspect you couldn’t get any two people to agree on the answers to these questions.

With that said, I feel I have used this printer enough to make a judgment call as to if this printer was a good buy.

Continue reading “Review: Printrbot Assembled Simple Metal”

GT2 Belt Drive Conversion Of Printrbot Simple

The early versions of the Printrbot Simple at about $300 were cheap enough for even the most cash-strapped hackers to put on their desks. Obviously, for that cost, a lot of design compromises were needed to keep it cheap. Sometimes, changes carry forward to the next iteration at no cost increase. One such improvement in the current version of the Printrbot is the belt drive. Unfortunately, if you have one of the late 2013 – early 2014 wood models, it is most likely being driven by a fishing line that loops over a rubber hose attached to the stepper motor. [jason] describes the process of upgrading the Printrbot Simple to a GT2 belt drive , using the designs posted by Thingiverse contributor [iamjonlawrence].

The trouble with the fishing line drive was that it would tend to get loose over time and needed to be pulled taut. Also, it affected precision when the line tended to wander over the drive shaft. The good thing with having rapid prototyping tools is you can make bootstrap improvements using them. Once the parts for the upgrade were printed, [jason] only needed some bearings, GT2 belts and pulleys to complete the upgrade. For those wanting to upgrade their old Printrbot Simple machines, [jason] guides you through the whole process via some detailed photographs and listing out the gotcha’s that you need to be careful about.