(This update (#7) is also posted on our kickstarter)

At the start of the project, I had a goal: 50 kits, me and my garage workbench.  A couple of days later, we surpassed that dream. As the project has grown in scale, we have had to ramp up our plans to meet the market demand. But something wonderful has happened… Printrbot has become something even better than I had originally planned.

Quadruple digit backers!  This is tremendous.  Thank you all for your support and enthusiasm. I want you all to know that the more money raised, the more resources I am pouring into the project to make it even better.  The printrbot is sturdier, stronger, easier to build, and more versatile than it was 3 weeks ago!  

Early on, I reduced the amount of linear bearings in the design to save a bit of money, but the price I have negotiated, due to the volume, is so good – we now have a total of 12 linear bearings…. 4 on each axis. 

To accompany the twelve 8mm linear bearings, we have ditched the “drill rod” and added machined, hardened, linear rod on all axes (yes, it is a word).  Paired with the excellent linear bearings, every axis is as smooth as silk!
Our motor supplier has dozens of motors to choose from, some are a bit cheaper than others, but you end up with reduced power.  For the X and Y axes, we chose to go with the highest power Nema 17 motors they sell – 4.2 kg-cm holding torque.  The spec for the Mendel printers on http://reprap.org/wiki/StepperMotor call for 1.4 kg-cm.  Why so much power?  Because we want to reward you with the best value possible.  And who knows, maybe you will want to upgrade to a bigger print bed and could use the torque.  Again, the volume of the order is huge and gave it us the option to go big.

 

Hot end improvements.  I don’t want to tip my hand here, since Carl Ubis, the designer, deserves the right to tell the world about his tremendous design modifications to his already proven hot end concept.  Let’s just say that the pictures you have seen of the hot end have little resemblance to the new models.  Rest assured, all improvements are being tested.  Every last bot in the bot farm will run a “Ubis hot end”– and run it hard, btw. The forcing factor for the improvements has been volume!  Way to go, people.  You folks are the ones driving this forward.   These improvements would have had to wait until much later if I was only funded to build 50 kits, as originally planned.

8x8x8 Laser cut Model…..  that’s right, it is a reality.  I am looking at one right now – and it is beautiful.  We thought long and hard about this move, but the feedback we received from the backers was very clear – “We want a bigger model!”  So we will be posting a new reward: the printrbot+ (printrbot plus) at the $649 pledge level. Again, this is specifically for those that wanted a larger model.  So we invite anyone wanting a larger build platform to jump up from $499 to the $649 printrbot+.  If asked what the difference is between the two, here is your answer: “printrbot+ is bigger (an 8x8x8 build volume on a heated bed), stronger, made mostly of wood, and it costs more.”  I will do a dedicated post with pictures, etc. in a day or two to formally announce the new model – with just a week left in the kickstarter project.

Electronics.  This has been a big challenge!  We based our “Printrboard” – featuring the electronic stylings of Laine Avina-Walker – off of the excellent Teensylu, a great design by StephS (http://reprap.org/wiki/Teensylu).  StephS and Laine are both members of my RepRap Builders meetup group near Sacramento – both extremely talented people.  My (untrained) requirements and Laine’s experienced ideas combined to make what we think is a standout all-in-one reprap electronics board!  Printrboard is made with surface mounted parts designed for automated assembly.  It is a 4-layer board, something unique, in our experience with reprap electronics.  4 layer boards are more complicated to build and more expensive, but they are much more versatile and have better heat dissipation than the typical 2-layer board.  We are testing a new 12 volt power supply (this board supports 12 to 19 volts) that has plenty of power and looks to be a good match for our board.  Even though we thought we would run it on 19 volts initially, we are going with a more standard 12 volts for several good reasons – not the least of which is better adaptability and compatibility with domestic and international power grids.

These developments have been coming in rapid succession and we are thrilled to offer the best possible product to reward you – our faithful backers! Thank you for taking this project beyond what I planned, and even dreamed. We look forward to delivering your little printrbot to you and having you as part of the family.

regards, 
Brook Drumm