New vs old: what goes on inside
I'm often asked “what's new improvements are coming to the Decent?” and my reply is “mostly neat things in software and firmware. We took 3 years to design a 'Turing complete espresso machine' that could improved like a computer can be.”
Now, of course, we're still improving the inside. But very little of what we do creates new features for customers. Instead, the work we do goes to simplifying and speeding assembly, lowering costs, and decreasing complexity.
First, we had to figure out how to make an espresso machine that did what we wanted. We couldn't focus on that, and also keep it cheap and simple to make. Our current model (V1.3) takes about 16 hours for us to make it. I know the real time, that work is done by our team. On top of that, about 4 hours of work is outsourced. So, figure 20 hours to build a Decent.
In the photos above you can see–on the bottom row–our “manifold”. That's the the sort of “train station” where hot and cold water comes in, various sensors check temperature and pressure, and valves decide where the water should go (espresso, flush, steam, etc…).
To make the Decent in small quantities, we mostly make things using a process called CNC. That's where you take a block of material and use a computer controlled drill to remove what you don't need. This is an expensive process, wasteful of material and very time consuming of very expensive machines. However, it's the only way to make complicated parts in small quantities. Moulds are very expensive (typically tens of thousands of USD$), take a long time (6 month minimum, with 18 months to perfect them being commonplace) and require unchangeable, mature, tested designs. Thus, moulding is not appropriate for a small company, producing small quantities of machines, and where our design is changing quickly.
The “manifold” on the Decent has 3 CNCed parts made of an expensive resin called “ULTEM”. We use it because it's incredibly inert: it's used medically for in-body parts and withstands high pressure and temperature. The big manifold, even at the quantities we're buying now (1000 at a time) costs us USD$120. The two smaller parts are cheaper, around USD$35 each. Add valves, sensors, the PCB, and you've got an expensive part. Plus, there are lots of tubes connecting everything. We color code every tube.
It's taking about 3 hours to assemble and test each full manifold.
Ben has been working 2 years on a unified manifold design, that takes all 3 ULTEM pieces, combines them into one, and in the process removes the need for 9 tubes. All the connectors become much easier to access as well.
On the top row of the photo, you can see a 3D printed prototype of his design. In a few months, we'll have small quantities of a CNCed version of this, that we can start testing. Once we get that all working, this manifold will start appearing in v1.5, or perhaps v1.6 Decent machines.
And once this part's design is mature, we'll switch to moulding it. That'll finally allow us to reduce the cost of making this part. But that's probably 18 to 24 months away.
And also note that this part is 100% backward compatible with all Decent machines. If a manifold were to break on an older model, we could install this new version in its place. All mounting point are identical, and the functionality is identical too.
I just wanted to share with you a bit about our longer term projects inside the Decent.
-john
Updated 2020/07/26