Original post from Paul Pratt on Facebook group
Raw cast items. I thought it would be interesting to show you all these items. I have that are unfinished and to show what goes into making the Robot. All stainless parts (apart from basket and screen) are created using investment casting. It is a very accurate way of making detailed stainless steel parts, the downside is it is expensive and time consuming. It is quite unusual in the coffee world to use this process, you can find the odd portafilter made in stainless steel and also Marzocco make a few parts in stainless too. After casting the parts are machined to size and then sanded and polished. Thankfully these days we here in HK only do some final stage polishing if there are shipping marks or scratches. The mirror polishing is very labour intensive since we start with a lumpy surface and then get to a mirror shine.
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On most of the items the starting weight is about 25-30% more than the finished weight. The arms are more or less the same weight raw or polished. About 50% of my cost on the stainless parts is at the post-casting phase - the machining, sanding and polishing. Aside from the actual mold for each item, there are also fixtures for each piece to hold the items during machining.
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In the photo of the arms you may be able to notice a small change to the design of the small plate that screws onto the main arm. I did this to clean up the top of the Robot when you look down onto it. Before you could see lines where the 2 pieces mated together, now they are hidden. Just a small change but looks great.
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