Let me elaborate on that as we appear to have solved the anodising issues we have been experiencing initially.
The technical explanation:
Additionally there's an increase in recycling increasing the amount of contamination:
The solution to this problem is to purchase the complete ingots, cut blocks from the outside parts, and use those for anodising.
This is easier said then done as these ingots are large, 1.2*1.2*2 meters weighing around 8 tonnes.
However we have that process up and running now and the first 30 chassis produced with those blocks are at anodiser 3.
Anodiser 3 is also a significantly larger Anodiser willing to work on our products (most don't). They can even reserve one bath exclusively for us if we can supply enough to keep it "busy" enough. The main output rate limiting factor however is the mechanical surface finishing, nobody has a bead blasting robot large enough to treat our chassis, so this is a manual process taking up around 2 hours each chassis part (4 hours for an Olympus server, 2 hours for an I/O).
Anodiser 1 we've been using for a while now has let us down there as, as I posted before in this thread they had allocated overtime, 2 employees willing to spending 5 evenings and Saturdays to bead blast around 30 chassis parts a week. However they never reached that quantity, and their motivation seemingly dropped over time, understandably as a lot of their work was in vain due to the zebra striping issue. Our own crew here has not been unsensitive to working long hours in shifts to only see 60% of all that hard work go to waste.
We now have an external company machining chassis parts in parallel to us, they have been machining 10 a week for the past 3 weeks (the same 30 which shipped to Anodiser 3). They have indicated they have spare capacity for a larger volume, however again the remaining limiting factor is the necessity of manual bead blasting, the people doing the bead blasting need to be skilled as well, it's very easy to do this wrong resulting in a chassis reject.
Obviously we're exploring alternatives paths to anodising, which may become increasingly troublesome in the future as more then likely usage of recycled materials will only increase.
To answer your question:
For silver we're still at around a 60% rejection for what is/was at Anodiser 1. They shipped half btw with the other half "promised" for today.
Anodiser 2 is doing black, it will most likely be like a 10% rejection rate.
Anodiser 3, new blocks (cut from the outter parts of the ingots), new process, optimistic for a 5% rejection rate!