View Full Version : BUILD LOG: Steel Frame, Aluminium Hybrid Design Thread

23-02-2016, 09:04 AM
Hello all,

I recently introduced myself on the new members page and am now starting a build thread which at this early stage is still very much a design thread.

I am aiming to produce a machine that will primarily be used for the following main jobs. (1) Simple routing of engineering plastics up to 18mm thick. (2) Simple routing of sheet aluminium up to 2mm thick. (3) 3D pattern work of epoxy tooling board of variable thickness. I imagine a rough cutting envelope in the order of 1000 x 500 x 200.

Almost certainly the job type will expand with use and familiarity so I have tried to ensure some future proofing in the design.

As the first build by Boyan seemed to cover a lot of my bases I have closely modelled my starting point on this design. The main difference is that whilst sticking with a steel bed and main gantry, the furniture comprises of a 10mm plate aluminium bolted design. I have opted for this route primarily because I have access to machining to produce these parts and also my welding experience is zero. Secondly I am hoping that this will allow some adjustability in setup, i.e. making sure ballscrews and so on are square and also scope to upgrade slightly easier in the future. Plate will be bolted to the frame with M8 fixings whilst bolted to itself with M5 fixings.

To date I have designed the X-Axis only and wanted feedback as to whether I am going down the right route before moving on to the next stages. Main specs are as follows

Steel: 80x80, 3mm wall thickness (is 3mm wall thickness enough to drill and tap M8 fixings?)
Aluminium Furniture: 10mm thickness, M5 bolting to self, M8 bolting to steel frame.
Linear Bearings: HIWIN HGR20R Rail, HGW20HC Bearings, Length 1300
Ball Screws: 20-05 C7 Ballscrews, Length 1200 supported with BK15 / BF15 end supports
Motors: NEMA23 SY60STH86-3008B driving 20 Tooth HTD5 Pulleys with a 1:1 ratio

Ballscrew end mounts are slotted in Z to allow Z adjustmet of the ballscrew. Y adjustment will be taken care of with shim spacing from the main frame. The BK/BF supports themselves are bolted to the mounts with no adjustment with the mounts themselves moving on the frame. The motor mount will also be slotted to apply the correct tension. Linear rails will be epoxy mounted.

I would love to hear any feedback so I can make sure I am starting on the correct foot! BTW, I realise the gantry is only supported on one side. The LHS will be similar in construction but different in design to house Y-Axis mechanics.