Frame Assembly

Before the 1.5 version of the Mendelmax came out, I was not intending on really going into any depth on the frame assembly as Techpaladin had done a stirling job of documenting the process. However, as Kludgineer has changed so many things in the 1.5 design, I'll attempt to document the build process. I suspect that someone else is out there, with more time and inclination, doing the same thing except better. Oh well.

Anyway, first things first. Before building the frame you need to have some bits from which to build it. These bits should include:

• Misumi (or similar) Aluminium extrusions, cut to length.
• Mendelmax 1.5 printed parts
• 8mm and/or 10mm smooth rod, cut to lengths as follows: Z axis - 2 x 350mm, Y axis - 2x 450mm, X axis - 2 x 445mm. I strongly recommend you check these for your flavour of Mendelmax as they can differ dependent on the build.
• A lot (maybe 120) of M5 10mm machine screws, similar numbers of M5 half nuts/pressed nuts (or the Misumi T-slot nuts if you're made of money), M5 washers, and then 4 x  40mm  M5 machine screws. NB. Some of the printed parts for the 1.5 will only accomodate for screws with a small head diameter such as hex-socket screws, so if you use M5 machine screws like me, you will also need 20-odd of these smaller headed screws (like this).

You should find, amongst the files on the Mendelmax 1.5 Thingiverse page, a PDF that, if opened with the latest version of Acrobat, will provide a 3d model of the 1.5 Mendelmax that you can rotate, zoom into etc. This is extremely useful in getting an understanding of what goes where. In saying that, what it lacks is labels, in particular labels indicating which piece of Aluminium Extrusion goes where - OK, this is a lie, if you expand the Model-Tree in the PDF every thing is nicely labelled but it's still not an easy thing to refer to when you're holding screwdrivers etc. So, for my own benefit I produced this:

The Mendelmax frame components are symmetrical front to back so I've only labelled the front facing ones on the diagram.
So, first of all, a few holes need drilling and some holes may need to be tapped.  The top horizontal 420mm pieces (A) each need 6mm holes drilled through them in order to attach the 340mm pieces (B), hole centres are 70mm in from each end. I recommend you print the 70mm jig that is on the 1.5 Thingiverse page as it makes it pretty hard to screw up the hole placement, if you can't work out how to use the jig you may want to try an easier project. If you don't have a drill-press and instead use a handheld drill, it may be worth drilling from either side of the extrusion so the holes meet in the middle to ensure you have alignment as close to square as possible. Next, you need to tap M5 holes in both ends of all 4 of the 300mm extrusions (C) and either one end or both ends of the 340mm extrusions  (B), if you tap both ends of the 340mm pieces, you won't need to use a self tapping screw to secure a printed part later on. Tapping holes is one of those things that you can easily screw up (hah!) if you've not done it before so I recommend practicing on some of the parts that don't need tapping, the bottom set of 420mm extrusions (D) would do nicely. The YouTube also has some good videos showing how to tap a hole.
Right, once holes are drilled and taps are tapped, assembly may commence.
I started with the base of the frame, consisting of 4 x 300mm extrusions (C) and 4 x 420mm extrusions (D). It's all pretty simple from this point onwards, it won't take you long to work out how to get your chosen M5 nut into alignment in the slots on the extrusion to accept a machine screw and after that it's all gravy (for a while).

Rather than exhaustively going through the build step by step, here are some pretty pictures instead:

Only thing to note about putting the front and back together is that if you use the same Y-mounts as I did then you're best to install them first, then put the L shaped printed corner pieces on.

Here's the completed base with one of the upper pieces placed on top, the 420mm extrusions (A) are attached via 40mm M5 screws through the 6mm holes drilled in the cross member and then into tapped holes in the ends of the 340mm pieces (B).

Once the two diagonal sections are assembled, they need to have the 'lower vertex upper ' printed parts attached to the ends of the 340mm extrusions (B) using either self tappers or M5 screws dependent on your prefs (I used M5). You should do this before joining the front and back diagonal assemblies together. Again it's all pretty simple from this point onwards and you'll soon end up with something looking like this:

Oh yes, very pleasing.

Ok, I know I have skipped describing several crucial steps here; Like installing the smooth rods, building the X ends and the extruder but I will cover those bits in a future post, probably.

I think this will do for the moment.