It’s almost a year since I got my CNC 6040 Router and I’m still happy with my machine. But since I’m using the Router more and more for milling aluminum it started to reach the limits of its capabilities. I made a list of upgrades I would like to do and the easiest upgrade that would improve the machine the most was the machine bed. So this is where I started.
There are three reasons for the upgrade:
Most CNC 6040 routers come with aluminium T slot profiles that function as the machine bed. M6 hex bolts are used as T slot bolts and threaded aluminium strips function as the clamps. In the end it works but the hex bolts tend to slip when you try to fasten them. Also some badly located bolts, that secure the profiles to the machine frame make it difficult to slide the T slots clamps in place. You have to use some force to get them in place. It works but it isn’t really pleasant to work with.
Another inconvenience with the original setup is that the bed isn’t flat. My machine bed had a couple of millimeters difference in height in some places. Such differences are way to much for projects like engraving.
When working with materials like wood en plastics, you don’t need to apply much force to take material away. Wood and plastic are very soft. When you try to mil metals like aluminium the amount of force required to engage the material with the end mill is much higher. With the CNC 6040 this causes the flimsy aluminium profiles to bend. Because the end mill is never 100% balanced the force applied to the machine bed varies with every revolution of the tool. This therefore causes vibrations. In fact the bed functions almost like a trampoline that catches the tool and then pushes it back upwards. As a result of these vibrations the
shiny surface finish of the aluminium is ruined and it creates a loud noise is.
Upgrade options to consider
Before I start a project I always do some research. From this research I found two videos from other CNC 6040 owners that had upgraded their machines.
I have to commit that this looks really clean. If optics where the deciding factor for me I would have chosen this option. But the price quote I got for a 24 mm plate was over 300 USD and that was just for material, no screw threads holes included. Also, aluminium screw threads are not the most durable threads. Especially when you use steel bolts and metal dust/chips between the threads accelerates friction wear. Rick mentioned in his video that plate was donated , so I think he made an excellent choice in his situation 🙂
Via this video I got introduced to this very clever hex screw inserts. Edward used them together with a wooden waste board. He bolted this to the aluminum profiles of his router and the result looks really nice.
Because I want to do a lot of Aluminium projects on my router I think that a full wooden machine bed wouldn’t be strong enough. But I didn’t want to spend too much money so the full aluminium bed was also out of reach. I decided to combine the two options.
For this first layer of my machine bed I bought a 15 mm steel plate. I payed 170 USD for it. A solid 45 KG should be heavy enough to not bend or vibrate as much as the aluminium profiles. For the second layer I bought a piece of 18 mm birch multiplex together with the E type 10 mm M6 hex screw inserts.
I bolted the multiplex down with nine M5 allen bolts. The pattern of the 9 screw threads can easily be used to swap de multiplex board for another type of fixture or a machine clamp.
The next step was milling the holes for the inserts. I used a 1/4 inch carbide router bit that is perfect for milling multiplex. All the 96 holes where milled in a hour. Because the inserts can easily damage the wooden screw treads I did the first couple of inserts by hand. When I got a feel for the amount of force they could take I switched to the cordless drill. To make sure the inserts wouldn’t come lose over time I used a small dot of wood glue.
With leveling the fixture plate I had to change my original plan of using a 25 mm router bit. When all the materials were delivered I did a small test and found out that leveling the plate with a 25 mm router bit wasn’t going to work. The spindle is out of tram. Out of tram means that it’s not 100% perpendicular to the machine bed. When using a large diameter tool I got some pretty ugly tool marks. I didn’t had the tools to fix this so I decided to use a smaller router bit with a small step over. This resulted in a nice and smooth surface. This change left a small stroke of material on the sides of the board. I can always fix this when I have tools to align my spindle.
The last CNC operation was milling the horizontal en vertical lines. These are very convenient when aligning the stock material. I used a ⅛ inch 30 degree engraving bit that made a 2 mm deep cut.
The last part of the project was sanding the board. For this I used grit 800 and 1200 sandpaper. To make sure that I didn’t created any differences in height, I used a nice and square piece of wood and systematically sanded board. The result was a silk smooth surface with a max curve of 0.15 mm. Not bad at all.
Testing the new setup
To test the rigidity of the new setup I machined some 6060 aluminium and the difference with the old setup is huge. The vibrations in the machine bed are gone. A 6 mm depth of cut went without any problems. Also the axial surface finish is now improved till the point that you can’t feel any tool marks when you use a good finishing strategy.
The hex screw inserts are working really good. No more slipping hex bolts or difficulties getting clamps in place.
I’m very happy with the overall result. The material cost of the steel, wood and inserts was around 200 dollars. After working several hours with the new setup I think it’s 200 dollars well spent.
Fusion 360 File
Via this link you can download the fusion 360 file for this project.
- Birch multiplex/plywood 18 mm x 390 mm x 590 mm
- Steel plate 15 mm x 770 mm x 490 mm
- 96 x hex screw inserts E type 10 mm M6 (ebay)
- 1/4 inch end mill (Banggood)
- 1/8 inch end mill (Banggood)
- 1/8 inch 30 degree engraving bit (Banggood)
- sandpaper 800 and 1200 (Banggood)
- 9 x washer ID 5.3 mm OD 14.7 mm
- 9 x M5 Allen bolts (Banggood)
- M5 tap tool(Banggood)
It might be helpful to mount the rear screw at the clamp upside down.