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The casing is just a rectangular plastic box with some holes in it, I'm sure you could get some made at that price. Even if the PCB costs 5x the quoted price,

The casing is just a rectangular plastic box with some holes in it, I'm sure you could get some made at that price. Even if the PCB costs 5x the quoted price, you're still rounding down to $1. That said, I have no idea what production costs are for something like this.

janekm 6y ago
I can understand how it may seem that way when a plastic takeaway box costs $0.1, why should this cost any more... The article's cost assumption is just based on the cost of the raw plastic material, which is hilarious (3D printer time doesn't really come free). But in more realistic mass production you'd make a mold, and the cost of the mold is dependent on how many "shots" you want to get out of it. Making plastic parts at the cost of takeaway boxes requires expensive high-volume molds. At 10k volume you'd be happy to get the box for $1 including amortised mold cost (though in reality the box could be much smaller, reducing mold & material costs some).
jononor 6y ago
The casing is about 2 hours 3d-printing a piece. That is 20'000 printer hours for 10k units, giving a machine-time cost of 0.025 USD (including plastic). That is off by a factor of 10-100, at least. For injection molding, one would need to make the molds. That would cost probably more than 1000 USD, excluding engineering costs (the design is not injection molding ready). Amortizing the mold costs over 10k units alone would be 0.1 USD per unit. Then comes actually making the parts. Maybe 0.5 USD is doable. I checked an off-the-shelf casing (no custom molds needed) it was quoted at 0.20 USD at 1K units - but this then needs to be CNC machined on 2 sides to add the necessary openings. Probably 1 USD a piece, at the least. The costs in the scientific article does make any sense. It is really sad to see that it gets through peer review so easily... I mean OK that the scientist does not really know what things cost to produce, but then they need to consult someone who does! Ask a manufacturing or even a design house for a cost estimate. Quality check your numbers at least a little bit.
jononor 6y ago
I would estimate the PCB costs, excluding Assembly time, to be 10x the quoted price.

janekm 6y ago

I can understand how it may seem that way when a plastic takeaway box costs $0.1, why should this cost any more... The article's cost assumption is just based on the cost of the raw plastic material, which is hilarious (3D printer time doesn't really come free). But in more realistic mass production you'd make a mold, and the cost of the mold is dependent on how many "shots" you want to get out of it. Making plastic parts at the cost of takeaway boxes requires expensive high-volume molds. At 10k volume you'd be happy to get the box for $1 including amortised mold cost (though in reality the box could be much smaller, reducing mold & material costs some).

jononor 6y ago

The casing is about 2 hours 3d-printing a piece. That is 20'000 printer hours for 10k units, giving a machine-time cost of 0.025 USD (including plastic). That is off by a factor of 10-100, at least. For injection molding, one would need to make the molds. That would cost probably more than 1000 USD, excluding engineering costs (the design is not injection molding ready). Amortizing the mold costs over 10k units alone would be 0.1 USD per unit. Then comes actually making the parts. Maybe 0.5 USD is doable. I checked an off-the-shelf casing (no custom molds needed) it was quoted at 0.20 USD at 1K units - but this then needs to be CNC machined on 2 sides to add the necessary openings. Probably 1 USD a piece, at the least. The costs in the scientific article does make any sense. It is really sad to see that it gets through peer review so easily... I mean OK that the scientist does not really know what things cost to produce, but then they need to consult someone who does! Ask a manufacturing or even a design house for a cost estimate. Quality check your numbers at least a little bit.

jononor 6y ago

I would estimate the PCB costs, excluding Assembly time, to be 10x the quoted price.