At long last, we have enough information to put out a meaningful update to the Kossel's schedule.
First, let's start with the BOM of the Kossel. For those new to manufacturing, the BOM is the bill of materials - a list of all the components that go into making up the Kossel. The current BOM is a work in progress; it is reasonably complete in the sense that it captures all the custom made components to build one of the configurations of the Kossel (in this case, the full size Kossel Pro, 750mm tall, 360mm triangular structs, with heated build platform). What it does not include are all the fasteners that go into the Kossel; adding the fasteners into the model properly actually will take 2-3 times as long as adding the main design components, so this level of BOM completion is a reasonably acceptable compromise. (It will become complete, down to the last screw, in a matter of days; this then gets sent to our packaging supplier to help with kitting the subassemblies). When complete, we estimate close to 1000 individual parts going into the final BOM (we count each individual fastener as a part, since we are selling a kit, the expectation is that everything you need to build the machine is in the box).
The items highlighted in yellow are custom manufactured items for the Kossel. As you can see, this comprises of a significant portion of the BOM. In this group are made-to-order components such as our linear rails, carbon fiber structs and borosilicate glass plate (which are cut to order), as well as OpenBeam designed and manufactured parts, such as the actual OpenBeam extrusions themselves, the corner vertexes, and all the injection molded parts. Also in this category is the Brainwave Pro (we decided to change the name to Brainwave Pro after consulting with Matthew Wilson, the designer of the original Brainwave). Each of these items have been in manufacturing for a very long time. Let's take a look at each in detail.
Injection molding is what sets the OpenBeam Kossel Pro family of printers apart from the rest of the printers out there. It is a painful process to get started on, but the resultant part is much stronger than anything laser cutting (DeltaPrintr, Kossel Clear) can produce. The material we are using for injection molding is EMS Grivory GVX5H. It is a high performance, 47% fiberglass reinforced nylon copolymer that was created by the Germans and Swiss to replace die cast aluminum parts. We have been using EMS Grivory for our joining brackets now and we have had great results with it. It is a good compromise on part cost and stiffness and it will allow us to ramp production to meet future demands.
OpenBeam signed off on the injection mold designs on March 5th. For those interested in what goes on in the construction of an injection mold tool, please take a look at our old blog entry here covering the original OpenBeam mold. This time around, we commissioned 4 molds to manufacture the 15 custom parts for the OpenBeam Kossel.
The current projected end date on the injection molding is April 19th. This is the "T0" date, where the first shots of plastic are shot into the mold and parts are made. We have to approve the T0 parts (or make modifications as the case often is) to tune the process to get good parts. Our injection molder has been really good about getting usable T0 shots on past projects, but we will never release the full 150+ set order in one go without the sampling. Due to the project running late, however, I will risk buy (ie, buy sight unseen) the T0s for the early bird kits, so that if the T0s are successful, we can ship early bird mechanical kits right away, instead of waiting for our turn again on the injection molding presses.
Based on this schedule we expect to be able to ship early bird mechanical kits on or about April 28th, and the balance of the mechanical kits on May 15th. We will hand kit the early birds to get them to backers ASAP and we will go through our normal kitting channel for the mechanical kits.
Our production quantity of vertex extrusions have arrived at our machinist in Shoreline, WA and we are finishing up the production fixture. We switched to a CNC 4th axis setup for machining these parts to eliminate having to reload the parts.
As a side note: 12 years ago, when I was a student-mentor for FIRST Robotics, Sherline Tools sold us a CNC mill and CNC lathe to get our robotics lab started at a really steep discount. That was my first real intro into engineering. I was more than happy to buy one of their CNC tables for this project. :-D
We do not expect the vertex extrusions to be a gating item in kit delivery.
Electronics and Software Integration:
Electronics and software integration have been giving us a lot more trouble than we'd like. As of Thursday of this past week we've validated the board electrically; turns out, older variants of Marlin broke the bed levelling switch logic, and newer variants of Marlin fixed it, but Johann's implementation of G29 auto levelling code had been taken out of Marlin head. Johann will be working on porting this back into the most current version of Marlin, as well as testing FSR bed levelling and SD Card printing capabilities of the new Brainwave Pro.
The OpenBeam Kossel Pro will NOT ship with FSR support (as the configuration has already been locked for manufacturing), but we will be testing FSR support and releasing documentation on how to retrofit for FSR bed levelling.
The boards that we are currently testing with are hand assembled by PCA Corporation in Bellevue, WA. While their worksmanship is superb, hand assembly is way too expensive a process to use for mass production. Our next set of boards will be built by our contract manufacturer overseas using robotic pick and place machinery, and will feature "design for test" features on the board. We will be performing 100% testing on all boards before they leave the factory; to aid in this, critical key test points are bought out to the bottom of the PCB, which are then contacted by a custom designed (and 3D Printed) test fixture with a bed of pogo pins. With the pogo pins in place, we can energize the board and "exercise" all the components on it, before flashing on the production boot loader.
The catch is, with over $20,000 on the line for the production run, we want to get about 2 weeks of solid testing on multiple printers on these prototype boards before launching the production run. Even after launching the run with the contract manufacturer, we will need to do what is called a manufacturing pilot, where we verify that the test procedure put in place, as well as the contract manufacturer's tooling (such as solder paste stencil, pick and place programming, etc) before releasing the rest of the boards to the build. Remember, it is awfully expensive to rework boards.
We are building a total of 450 Brainwave Pros for launch. We arrived at this figure in order to hit the price break for the TI DRV8825 motor driver chips, and that also happens to be how many Atmel processors are in a tray. We have already purchased the long lead time components and they are sitting at the CM. This is important, because we can be looking at 20+ week lead time on components.
Based on the above projections, we expect to ship early bird full kits on or about May 16th and the balance on or above June 6th.
Kitting and fulfillment:
As mentioned above, the early birds (as well as manufacturing pilot units, built for validating the instructions) will be kitted by hand here in the US. The final assembly will always be kitted in the US, due to the high amount of domestically produced parts, but sub-assemblies will be kitted overseas. We will be air freighting the kitted sub-assemblies in to get kits into people's hands as quick as possible.
We plan on using Amazon Fulfillment for kickstarter reward fulfillment in the US. We are still finalizing our international shipping arrangements at this time and I will have more on this in a few weeks.
That's it for this update, back to work for all of us here on the Kossel team.