Our new extrusions are in – and they are AMAZING.
Six months ago, things were looking pretty grim for OpenBeam. Our old extrusion vendor had delivered 3 consecutive batches of bad extrusions. We’ve received extrusions that passed their quality control that are warped, fork lift damaged, or corroded beyond recognition. With our inventory depleted, most of our cash got tied up in bad product that can’t be sold, and back orders piled up. Truth be told, if we did not find a new, qualified vendor in time that we can source the extrusions at a reasonable enough price for, we would have had no choice but to go out of business.
Fortunately, this didn’t happen. About a year ago, over cups of Chinese tea, I laid out the direction of business expansion to my father. We decided to develop our import and logistics capability to offer a cost advantage in sourcing commodity components such as stepper motors, pulleys and bearings that goes into 3D Printer kits, in direct response to our first 3D printer offering being cloned within weeks of launch. That decision ended up saving our company, as gaining the ability to ship Less-than Container Load (LCL) meant that we were no longer restricted to buying from American suppliers for our extrusion.
In an LCL shipment, the cargo is collected and bought to a container freight station (CFS). Depending on the terms of sales (Ex Works – where the supplier’s responsibility ends in producing the product and leaving it on their shipping dock, or “Free On Board” where the supplier’s responsibility includes getting it to the dock (traditionally, over the side of the cargo ship), either the supplier or the freight company provides a pickup service to bring the cargo to the CFS. In our case, we are buying ExWorks, so Expeditors International, the company I am using, provides local trucking service overseas to bring the cargo to the CFS. Once at the CFS, the cargo is consolidated with others into a container. This is then loaded on the next available Seattle bound ship. From most of the common ports in Asia, there is a weekly sailing, so in our case, we have to get our cargo to the CFS by noon on Tuesday to catch the boat sailing that next Sunday. After about 3 weeks on the water, the container ship docks at port of Seattle or port of Tacoma, and the container gets unloaded, through customs, and the cargo is made available for pickup at the local CFS. (I opt for local pickup, because I have a day job, and it’s somewhat easier to take a long lunch to go pick up the cargo, than to have to take a day off and pay for delivery and wait for the delivery).
Setting up to ship LCL is not a short process; and it requires posting a $50,000 bond with US customs and paperwork to become an importer. However, once in place, this is a very cheap and reasonable method to move large bulky cargo internationally. In fact, it is cheaper to ship a pallet of aluminum extrusions via LCL than paying Fedex to drive it up from California, with a transit time from Asia of approximately 20-25 days. Once you factor in that Asian mills usually are more responsive (the one we are using turns orders around in 2 weeks, instead of 8 weeks for my old supplier), however, the lead time becomes quite competitive too even factoring in a 3-4 week journey across the ocean.
Early this year, as I was standing on the loading dock listening to another excuse as to why I’m staring at another pallet of garbage extrusions, how the extrusion mill wouldn’t be heartbroken if they never saw another order again, etc, I’ve already had multiple quotes from American and off-shore extrusion vendors in my back pocket. The final “reject” rate was between 5-6%, but this is highly debatable. In my haste to sort through the extrusions, I’ve missed quite a few on my first pass that was warped, only to find it jamming up the auto saw later. But even at 5% rejection rates, the fact that someone would think that a 5% manufacturing defect constitutes acceptable is mind boggling. Consider for example our pre-cut kit. It contains extrusions cut from 8 pieces of 1 meter length bars. If 1 out of 20 pieces (5%) are problematic, I will have to do a 100% inspection or 2 out of 5 kits I manufacture will have defects. This is simply not a sustainable way to run a business.
One of the reasons our new extrusion vendor overseas took so long to spin up is because they are willing to do cutting and kitting of extrusions for us – and there were a lot of back and forth in communicating the cutting list and packing procedures. Cutting and kitting had traditionally been the choke point in the OpenBeam business. The old process consisted of me driving close to 100 mile round trip after work with as many pieces of aluminum extrusions I can fit into my Mazda5 “Urban Deployment Vehicle” (I am not at the stage in my life yet where I am willing to admit to people I drive a Minivan… ) to my friends at MicroRAX to run the extrusions on their autosaw. OpenBeam had to absorb any defects in manufacturing as well as manufacturing losses; for example, 8 meters of OpenBeam goes into each pre-cut kit, but the actual sell able extrusions in the pre-cut kit is only 7.5 meters. 500mm of OpenBeam disappear in the form of little drops and a big pile of aluminum shavings per precut kit made – and that’s assuming that the saw behaved. If a badly warped piece of extrusion that I missed on first pass inspection jame the saw that extrusion piece along with the other three that are being cut simultaneously with it gets written off as scrap. This is why we temporarily pulled out of the Kossel extrusion kit business – the labor involved for us was too high to compete against someone reselling a compatible extrusion that had been cut for them at the factory.
About two weeks ago, the cargo ship Akinada Bridge carrying the OpenBeam container docked in Tacoma, and after clearing customs, I hauled home my loot from the container freight station.
Given our sour experience with our previous extrusion vendor, we set out to inspect our extrusions for two things: Flatness, and accuracy of cut. The latter is extremely important for 3D printer kits.
For flatness, we inspected a random sampling of extrusions on a granite inspection plate. Granite inspection plates are precision ground blocks of granite. Their job is to set up a reference plane upon which measurements can be taken. This particular plate we used is made by the L.S. Starrett company. They, along with Brown & Sharpe, Mitutoyo, are considered to be some of the finest metrology instrument manufacturers in the world. The plate we have is a Class A inspection grade pink granite table; the table is flat to within 10 microns across its 36″ x 48″ surface.
To inspect for flatness, we randomly pulled 5 samples of each color out from the different shipping containers. (it is CRUCIAL that the sampling be as random as possible, and not pull the top 5 pieces of box 1. Years ago on my engineering job, our inspection department is known to take short cuts. They inspected a lot of medical battery cases from one box and accepted the shipment. Little did they know the vendor had shut of the injection molding machine to go to lunch halfway through the production run and there was a batch of undersized parts from the machine warming up after lunch. The parts didn’t get caught and quarantined and the production line went down as a result.) We place the bars onto the granite table and check for signs of the bar rocking. Then we take feeler gauges to probe the maximum size feeler gauge that can slide between the granite and the aluminum without lifting the bar off the table.
What is simply amazing to me is that 3 of these 5 bars don’t exhibit any rocking at all, and I was hard pressed to slide the 0.04mm feeler gauge – the thinnest in my set, by the way – in. On the worst warped piece, I can slide the 0.1mm gauge in. I repeated the test by putting a dial test indicator on the aluminum and pressing down onto the bar to see if I can measure any deflection. On over 50% of the parts, the total deviation is only 0.02mm from when I press down on the extrusion.
Allowable warp on the extrusion is 1.1mm per meter, per Aluminum Extrusion Council‘s guidelines. These extrusions are, at worst case, an order of magnitude flatter than what the AEC allows. This is a far cry better than the 3-5mm warp that we were seeing from our other extrusion vendor! 3-5mm warp, in a 1 meter length, is very very visible to the naked eye. It certainly makes me question the other supplier’s quality control procedures.
Next, we check for accuracy of cut lengths. To measure length, we stood the extrusions up and used a Mitutoyo Digimatic Height Gauge to measure the distance between the granite reference surface and the top of the extrusion. This method is somewhat faster and less prone to parallax errors than measuring with a pair of digital calipers. The cut lengths are most critical on our new Mini Kossel kit, so we pulled 3 sets randomly to give us 36 samples to measure. (This was before we merged the design, at one point I still had 12 pieces of 240mm in my design for the Mini Kossel). I’ve placed the metrology results in an Google spreadsheet here.
The results are incredible, once again. The calculated standard deviation – a measurement of how tightly clustered the spread is, is a mere 0.03mm. As a comparison, my hair clocked in at 0.08mm. If you were to assume that the distribution of the cut lenghs is Gaussian - and that’s a pretty safe assumption to make – 99.7% of all samples fall within a six sigma (6x standard deviation) spread around the mathematical mean. In other words; given the standard deviation of 0.04mm; 99.7% of the measured values will fall within 0.04*3 or 0.12mm of each side of average. To be safe, I can claim +/-0.3mm tolerance on the cuts (which is damn good, by the way, that is approaching machine shop tolerance for machined parts), and in selling 1000 pieces of extrusions, I may get 3 returns for being out of specification on cut length tolerance. That is seriously impressive, and certainly something that I can build a profitable business upon.
I measured the precut kit lengths too, but as you can see from the data, that was a strictly academic exercise. In fact, I stopped half way through and just packed up to go home.
Armed with this data, I am happy to announce the following:
A) Extrusions, in the form of 1 meter long bars, are now on their way to Amazon fulfillment centers, and will be back in stock shortly. We can now guarantee the new extrusions to 0.5mm per meter flatness.
B) We will be re-entering the Kossel extrusion supply business, with the following difference: we are contributing members to the Open Source Hardware community, we offer free shipping on our extrusion kits (free second day shipping for Prime households), our extrusions are competitively priced, available in black anodized, and we guarantee their cut accuracy to +/- 0.3mm.
C) We have removed our biggest road block for building pre-cut kits; dealer backorders are now being processed, and there will be a few kits showing up on our web store. In a month or so, when our next shipment arrives, we will start selling precut lengths a-la-carte with Amazon Prime fulfillment as well.
E) With our confidence in our new supplier, we have already placed a very large order (bigger than ALL the previous OpenBeam orders, combined to the American supplier, including from our original kickstarter campaign). This, along with the competence of our new supplier and the fact that they only need 2 weeks instead of 8 to turn an order around, hopefully resolves our supply chain problem and having to hang an “out of stock” sign for months at a time on our web store.
F) We still have a handful of extrusions from our old vendor; we will be getting rid of these in a fire sale to recoup the money sunk into it. Basically, these are extrusions that may have flatness or cosmetic issues. We don’t feel good selling them at full price, so we’ll just sell it at a large discount to benefit our local maker community. Details will be announced soon.
We are happy to say that after an incredibly long and dark few months, the light at the end of the tunnel wasn’t from an oncoming freight train and we are happy to be on the right path again. With the production issues behind us, our next order that is about to leave for its ocean journey is for a whopping 13km of extrusions. This single order (and not including the 3+km that we just purchased as a “test run”) is more than all the extrusion orders to the old vendor combined, including the material for our first kickstarter campaign, and we expect to be placing an order of similar size regularly to ensure that we stay in stock. We are happy to be growing, and we thank you, our loyal customers, for supporting Open Source Hardware.
-=- Terence, Rachel and the furry monster puppy.