Quote Originally Posted by NordicCnc View Post
The way I plan to solve this is whenever I am machining aluminium / very light steel, I will use a jig that I put on the table, which will then decrease the Z-clearance. This should work the same way as having an adjustable bed.
The requirement is a large work area, so a moving gantry design and making it as good as possible is my goal. This of course means that it wont be as rigid and as effective for aluminium / very light steel. This is a trade-off I need to make, as I don't have the budget or space to build 2 machines right now.[/QUOTE]

That's a good solution and one I'd take if building for my self with your requirements.


Quote Originally Posted by NordicCnc View Post
That is a nice looking machine you've built! Great idea with the 4th axis too.A few questions if you don't mind:
  1. How does it perform in aluminium (tool, cut depth, feed rate)?
  2. Do you have a build log somewhere?
  3. What is the Z-axis clearance and working area?
  4. Any reason why you went with L-shape design, instead of using say 90x180 box section profile?
  5. Are the surfaces where the rails sit on the X-axis machined or shimmed?
  6. What is the reason for having one rail top mounted and the other one front mounted on the X-axis?
  7. Are the gantry sides also made of 120x80 profile? How are those mounted to the gantry?
  8. The Y-axis rails appears to be top mounted. Why not side mounted?`Is it to make design simpler with the profile gantry sides?
#1 Cannot tell you this because I've never used iit myself, I only built it, and the owner only cuts woods with it as far I know.

#2 No this is a design I build and Sell.

#3 Z-clearance = 250mm Cutting dims Y1300 x X800

#4 Yes it's a much stronger design than a single piece of profile. It's my own design that I've used for years and it's well-proven on lots of machines.

#5 The surfaces are made flat and on the same plane by coating with a fine spread of Epoxy metal (not epoxy resin) and then machine frame is turned upside down and placed on precision Granite surface table.

#6 The fronted mounted rail is to give maximum clearance under the gantry and the top-mounted rail is to give greater spacing between rails and support the Z-axis rear plate.

#7 Yes 120x80. They are mounted by bolting into the lower flat profile from the top. The top profile is bolted to the flat profile from the underside, there are also aluminum keys inserted into the slots to stop any movement.

#8 It's difficult to align the rails parallel to each other when side-mounted. It's also much more difficult in regards to them being on perfectly horizontal and vertical planes. If the surface the rails mount on is not perfectly vertical then the gantry sides will form a V if viewed from front plane, likewise, if the surfaces are not parallel to each other they will form a V if viewed from Top plane.