Skrekstore — blog

Producers of garbage

Posted in Manufacturing, on

We won't sweep it under the carpet. When you produce things, you produce waste. Victor Papanek's ghost is unavoidable, always whispering "In an environment that is screwed up visually, physically and chemically, the best and simplest thing that architects, industrial designers, planners etc. could do for humanity would be to stop working entirely”. It's not the prettiest topic, probably why it's seldom brought up by manufacturers. We won't debate the ethics around manufacturing products at all, and anyway, our stance is kinda made. Still, we feel somewhat obligated to briefly touch upon the implications.

Ok, so manufacturing a product is most likely not positive for the environment. To take one example, our aluminum components; extracted from some mine (probably in China), smelted into rods, milled away to 20% of its volume, electrocuted in salty-chemical water, and then flew around the globe. You get the picture, it stings, doesn't feel good... However, the production of both standardized and custom components are opaque, also for us as sourcers. It's a complicated picture with a myriad of parts and energy consuming processes, making it difficult to measure even a proximate effect on the environment.

One of the sources of waste in this chain of events is packaging. Not that it's any easier to measure its actual footprint than anything else, but at least, a lot of it sits there in our plain sight. Obviously, there's the little cardboard box our product is presented in, plus, the PE padded envelope it arrives in. But this is just on the consumer end. Every single one of our components comes is some form of tray, often wrapped in plastic, padded with plastic or paper, and then put in a cardboard box. 

The image above shows just a portion of all the packaging we received from our distributors and manufacturers (who probably also got their (raw?) materials in some other pieces of packaging). Our production case might be special, we don't really know how this is normally done and organized. Our assembly was in Norway, so we got parts sent in from all over the world; France, the UK, Spain, the US, and China. Sounds cool, but most likely highly inefficient. Especially since protective packaging feels soooo unnecessary.
Although, avoiding protective packaging seems hard; you basically need to have all the components coming from the same factory. In our experience, national proximity isn't even enough. For instance, the circuit boards we made at Hapro were heavily padded – and that's just an hour drive away from Oslo, shipped with the company's own courier.


There's no great conclusion to this rambling. Basically, what we're trying to say is that what we end up with as a consumer, is just the tip of the iceberg, we're at the tiny end of a fractal pattern; we get the small cherry on top of the larger energy cake. And it's a cake with obscured edges and ingredients. No, that's not exciting. Remember, the cake tastes like garbage.



Papanek quote from his book "Design in the Real World"



Posted in Manufacturing, on

We're not engineers, but making a physical product definitely required us to do some mechanical engineering. Working on DURR Beta's assembly, consisting of multiple parts and different materials, all fitting tightly together, really put us awe of all the thought and care that's put into every product... Even the low quality ones! We experienced a few things along the way that might help other novices: 

Learn from other's work:
If you're not familiar with this, get right on it: Break open other products, and reverse engineer! It doesn't even have to be similar in size or in product category. It's mesmerizing to think of all the man-hours that have gone into the design and engineering of everything from ball point pens to a electric cable winch. Try to understand the thought process behind the different solutions and acknowledge both good and bad decisions. 

Snap-fit was hard but rewarding:
SLS Polyamide for the back cover and screw-in battery cap had it's disadvantages. However, it enabled us in having multiple and replicable rounds of testing before we pushed it to the final production. After trials and errors we managed to construct a snap-fit geometry that held everything tightly, was reasonably easy to install, and spared us from using screws and/ or glue. The latter would most definitely prolong the assembly time, add parts and complexity, but could also make other components, e.g. the aluminum chassis, more expensive.

Don't stack too many deviations:
Every manufactured part deviates to some extend from the original drawings. In most cases, these variances are quite small, and they are usually found in the part's datasheet (often in a parentheses with a '+/-'). E.g. a part's height of 3.0mm can have a +/- 0.1mm deviation, which means its height ranges from 2.9mm to 3.1mm. At first glance this might not look like a big deal, but can in fact become one – especially if the deviations are stacked. We encountered this several times in the process, but perhaps most evident in regards to the coin cell's connectivity to its battery contact on the PCB. Adding up the possible vertical deviations on the aluminum, tape, PCB, battery contact, coin cell battery, + 2x Polyamide SLS, gives a range of +/-0.7mm. A height greater than the battery contact itself. Most likely, the variances would not add up only one way or the other, but if so, the battery would either be unreliably connected to the PCB, or not fit the enclosure at all.

Reiterate your thresholds:
Working with tolerances can easily give you tunnel vision; Everything have to be 0.15mm less to fit into its mating part. Or so it may seem. Not all parts are CNC machined out with the same precision, and not all materials are as rigid as it looks in your 3d software. So it's important to reiterate your threshold, and to keep in mind the material properties and manufacturing techniques. We weren't able to stay fully on top of this, but luckily avoided disaster by chance; Upon examination the hand made metal die (for the straps) deviated +0.5mm. This exceeded our unnecessary tight estimate of 0.2mm by quite a lot. But, because of the leather's flexibility (and durability), it only resulted in a slightly tighter buckle.

Injection molding vs SLS polyamide

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For most of the time developing DURR Beta, we were quite fixed on having the back cover and battery cap in injection molded PE plastics. CNC milled aluminum molds can make this a fairly affordable option that can produce up to around 100.000 parts per mold. However, up until the last phase before production, we looked at alternatives and ended up using SLS polyamide... again.

After, perhaps not the most extensive round of research for low-volume injection molding factories, we kinda settled on a British service called Protomold. They have a great support team, awesome webpages with live calculator tools, and they even sent us samples of the plastics we were considering. Low-volume injection molding really seems like one of their expertise and they also mill their molds at the same factory.

We'd really made an effort in making the geometry moldable, with all kinds of clever (at least in our humble opinion) solutions for difficult problems. However, when comparing the small volume we wanted of injection molded parts to SLS polyamide parts the price couldn't be overlooked; The service Sculpteo Pro offers batch discounts, resulting in almost a third of Protomold's price. Keep in mind that our parts are fairly tiny in size, as well as quite complex. Many many, larger parts with simple geometry might give a completely different picture. The difference for Sculpteo's batch prices also accounts when comparing with other SLS services like Shapeways and Ponoko.

A quick overview of the advantages for the two options:

SLS Polyamide (Sculpteo Pro; batch order):
· Cheaper (for the geometry, size and volume at hand)
· Freedom in geometry; no tools, draft angles, separation lines, etc.
· Allows testing and tuning, with the actual material.
· Flexibility in volume, especially if re-fills are necessary.

Injection molding (Protomold; aluminum mold): 
· Large range of materials/ plastics.
· Larger range in color. (You can even get your own plastic from a third party).
· Better finish, accuracy and quality (again we have small parts and really small features)
· Cooler. We're kinda sick of using SLS, and wanted to do like the big dogs. Some other time tho...

Also worth mentioning, we had a some problems with our order at Sculpteo. This might have been bad luck, or because of low staffing during summer. However, a delivery time of about 6 weeks when the order says 5 business days really held us back towards the end. Our shipment was continuously delayed due to machine issues and arrived in a number of smaller batches, which also led to differences in color and dimensions.

Not all parts held up to standards and were weeded out. The final result was acceptable for the finished product, but did leave room for improvements.

Things slowly coming together

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First proto-PCB to come out of our oven, to make sure everything works (it does!):