Pictured above is one of the early and more basic designs that the build will follow. Here I have focussed on the granite elements and the gantry design. The design of the Z axis and Y screw assemblies are only for proving principle. I fully intend to further design these elements later to provide more rigidity, functionality and environmental protection.

I will go into the design of the gantry in more detail in a later article. For now I will discuss the provisional assumptions that I have decided on for the specification of the build.

• Initial calculations and estimates suggest that for the assembly weights, I would need a minimum of 25mm diameter Ballscrew and probably 32mm ball screws for the X axis.
• At this stage I had decided without doubt that it would be fitting Servos on this build. In my mind I would be specifying 400 or 750W but I would confirm this mathematically at a later point in the build. During the design of the elements, I bared in mind the difference in size of the various servo's and took note of what design elements would need to flex depending on the direction I took.
• I had committed now to making a machine as rigid and capable as I possibly could, so I was intent to have a full feedback loop with the servos. This would require me to fit glass scales, as well as choose a controller that supports this functionality.
• After many a conversation with Phil Timpson & Kjetil Torkelsson and Chris Polanski to be honest I finally settled on choosing MESA as the controller. Particularly the flagship 7i95 controller supported all the requirements I had and was infinitely expandable.
• At this stage I was assuming a spindle with between 3.0 ~ 5.5kW to be used on the build. The build is taking place at my private residence and the workshop has only a single phase feed. I didn't really want to have 3 Phase installed. It is not totally off the cards though.
• I mentioned high accuracy, high repeatability glass scales.
• I decided that a full flood coolant was part of the plan.
• High quality and reliable limit switches were a must, as was an effective homing switch. I actually considered just how important, and sometimes overlooked is a high performance homing switch. Sounds really simple to be honest but it is often under spec'd. If you have a homing switch with poor repeatability, you are immediately going to get questionable results no matter how rigid your machine is. But of course, if your build has an 18 foot high Z axis that bends the aluminium frame like strawberry twists, you can fit whatever homing switch you like, you will always be chasing accuracy and good surface finish,
• I wanted to plan for environmental protection for the screws and rails. This could be with bellows or other possible solutions. this had not be decided at this stage, but I had to consider my options at the design process.
• DMM Servos were planned and the method of wiring I has settled on was the follow the manufacturers guidelines as closely as possible. At least that way, if I were having issues, it would be easier to eliminate noise from skimping on EMI Filters or whatever.
• At this stage I had planned to use the stand that came with the surface plate but extend this to provide further support and provision for the coolant drainage and filter system. This changed significantly as I continued through the build.
• After a lot of research and contemplation, I decided on using internally threaded sockets cemented into the granite. I chose not to use the normal resin approach as I wanted to achieve a more industrial result. I will cover of what cement I settled on in future posts.
• I would look to custom design and build and ATC system in the future. This was assumed in the process.
• I didn't need to worry about Probes and Tool Setters as we were already manufacturing these for EMG Precision Ltd.
• I had settled on fabricating a sort of plastic tank and filter system for the coolant drainage and probably a guttering type system for drainage. It clearly wasn't ideal and would cause me issues with cleaning you pile of chips, but it felt like this was something I would have to live with and settle for.
• I would plan to build some sort of basic enclosure to contain the flood coolant.

I am not a big fan of YouTube to be quite frank. I have never actually made any videos for it where I be the key speaker. But at the time of writing this, I think I will have a go at doing some video diaries of the next steps in the build. Let’s see how it goes when the foot is healed, and I can get back out there.

OK, So's that’s setting the basic scene for how I am expecting the build to go and with a bit of a vision of what the specification and functionality will be. Please comment on your thoughts for what I have discussed above. I welcome your constructive critique and feedback.