Here are some details of my aluminum honeycomb and MDO plywood composite table for my Onefinity.
I wanted a super flat and robust table top for my Journeyman. I am a hobby machinist as well as a woodworker. An extremely flat, stiff, and level table top is what I wanted for my CNC router. The flatness and ease of leveling this table exceeded my expectations.
The table top was fabricated by a millwork company in Mobile, AL. (http://deasmillwork.com/). The tabletop core is a ~ 1 5/8" thick aluminum honeycomb panel which was encased in 3/4" MDO plywood skins top and bottom. The millwork company has access to these honeycomb panels which are typically used in maritime and other applications (military?). Deas Millwork has developed their own proprietary process of preparing and sandwiching these panels between sheets of ¾” MDO plywood or other wood panels. Part of their process is machining the panel and edge banding them with a dense hardwood to encase and seal the honeycomb within a wooden skins.
The components were prepared dimensionally, assembled with polyurethane glue, and then cured while in a hydraulic press using 160,000 pounds of pressure. The cured assembly was then trued by edge sawing it in a Routech 5 axis CNC to assure that its edges were perfectly rectangular and square.
This table is FLAT, perfectly rectangular and square, and quite strong. It is nominally 4’ x 6’ and 3 1/16” thick for the Journeyman application. It does loose about 1/16” of length and width in the CNC for the squaring process but that is irrelevant from my perspective. It is secured to a Kreg leg set in my shop. I leveled the table using a Starrett machine tool level and then confirmed the levelness of the installed Journeyman rails. The squareness of the top is a huge advantage in assuring the Onefinity Y-rails are parallel and all reside in the same plane.
The waste board’s counterbored holes for securing them to the table top were machined by the newly installed Journeyman using a temporary jig. The waste board can be easily replaced in the future using the same mounting holes to the table. This maximizes the life of the table top and avoids any additional holes in the MDO skin in the future. This is my version of a quick-change waste board, secure from above system. The result is a level and square table that is quite stiff and robust.
As you can imagine, this setup allowed accurate tramming of the machine. Obviously, my machine is stationary and will not be moved.
I was invited to be at the millwork when this prototype was being built and captured some of the fabrication process in photos. I will post a few more in a subsequent post here on the installation on the Kreg leg set in my shop. So here are some photos of the table being fabricated.
The aluminum honeycomb before sizing:
The Medium Density Overlay (MDO) plywood pulled and ready to go:
The aluminum honeycomb prepared for edge banding and assembly:
Assembly and polyurethane being applied:
In the press for curing:
Cured and coming out of the press:
Out of the Routech after edge truing/sawing:
I missed the edge truing in the Routech for a coffee break! Here’s some videos of the Routech on other projects and yes, it is the real deal. Video - Deas Millwork
I requested an additional step that it be finished and cured with Acidized Catalyst Conversion Varnish in their paint line: