Hey everyone, I'll answer some questions and then some updates.
In regards to power, indeed there is no charge for power. I'm looking at a 500sq. ft. unit for $900 - power included. Even the 50A of power that this setup will draw. I
will have to pay for running the service from the panel but that should only be ~$1k. So if I run the oven for 150 days a year, I'm getting around $5k of power for "free." But hey, they've been well warned and that's the deal so I won't complain.
The boards are about 7"x5" each, oddly shaped, kind of like that zig-zag tetris piece. There is no particularly challenging placement on the board. There is one single 0.5mm pitch 8-WSON buck converter, everything else is TQFP, SOIC, and smallest passives are 0603. About 5 SMT connectors. Why the placement cost was so crazy from Macrofab, I don't know. That was $60k assembly cost, not including the component cost. Price didn't change regardless of whether they purchased the parts or I supplied them. That's pretty nuts. That's for a delivery date of
October 30th! As for cost per placement, I'm getting $10.66 per board for 5k from Macrofab. And this is still missing 2 large parts, a through-hole PSU brick that needs to be wave or hand-soldered, and a ~20x50mm PCB assembly that comes in JEDEC trays. That comes out to just around $0.10 per placement. That's quite high. I'll point out that PCB.NG was no better. They've currently spent over a month trying to get a run of 100 different boards from Advanced Circuits. Those boards are 4"x2" and have 2 through-hole rotary switches, and
that's it. Over a month. For 100 boards. AC says they have a part in stock, turns out they don't. Delay a week while they mill about. Say they're getting some in soon from a distributor, then they say the distributor lied and there is no stock. Mill around for another week. It took me all of 2 days to connect with my agent in China and get an invoice for 10k switches direct from the manufacturer. That is where I add the value here and why they are willing to go this route.
In fairness, the client will be paying nearly double this for their first assembly run with me. The difference being that subsequent assembly runs will be drastically cheaper. If I can run 1000 boards for $3 each within a week, I'm happy with that. That's $0.03 per placement, I think that's extremely reasonable, since I only have to pay myself and the landlord. AND they will be able to get moderate (100-500) quantities within a week if they want. Even if 2 weeks they don't need to pay me crazy expedite fees, nor deal with the long process of re-sourcing a BOM to suit the supply chain in China.
The pure parts cost on this board is low, maybe $20 total. There are two parts, a PSU and a specialized IC, that make up half the cost. The PSU I am sourcing direct from the distributor in China, the IC from Digikey but the price is actually higher overseas. The overall price difference between DigiKey and China is negligible. Passives are so cheap they're basically free. A reel of 10,000 resistors is $20 on Digikey. Not worth thinking about at these volumes. They are taking the risk and the initial expense so that they can focus on what they're good at, growing their business, and I can handle the nitty gritty PCBA details. Assuming their business survives otherwise I think this is a fantastic arrangement for both of us.
Of course, we will see how true this is once they sign the contract
. I hope that explains my reasoning better. If you don't have employees to pay, don't
need to be competitive on a large scale in the PCBA business, get power for free, and want to have fancy machines for fun, it's easier to justify.
And yes, 500sq. ft. is tiny, this will be a cramped room.
Here is my idealized room plan after getting the machine footprints and measuring the room. I believe I can get everything seen here for ~$120k, including a service contract and training. The PnP will have to come out quite a bit from the wall to allow room for access to the rear feeders, which may well break the conveyor chain. That will be annoying but I'll live with hand loading boards into the oven. Alternately I could place the magazine loader after the PnP and once it's full spend a few minutes feeding the reflow oven. But at least that gives me some time to leave the machine alone (we'll see how that pans out...). With a realistic CPH of 6-7k and 9 PCBs per panel I should get a panel every 10 minutes.