Gantry cnc base

My brother has a garage with some space for a CNC machine but the cost of most of the machines is very expensive. Alternatively, some of the cheaper ones utilize an aluminum frame. Considering the stiffness of steel and its cost we would like a steel frame. However, the structure still has to be capable of having a lifting procedure to safely lift the unit into the bed of a pickup truck. The design is still in progress and has a cost estimate of ~$600 so far (assuming I don’t have to pay a welder…). A large part of the design goal was to make as much as possible out of as few different “Make From“ parts. The structure is almost entirely made from 2.x4.x.12in mild steel tube, 2.5x2.5x.125in mild steel angle bar, and .125THK steel sheet. The head mounting interface is left up to future designs to occupy. I know my brother was interested in mounting a laser and the design could easily carry a plasma torch. I tried as much as possible to keep the tracks shielded from the region where splatter may impact the driving ball screws or the tracks. Likely, I will end up placing bristle brushes along the track just to keep the tracks free of debris and simultaneously being easily brushed aside when the gantry travels. The nominal/max volume before mounting a tool to the interface is:

X-axis: 31in ; Y-axis: 30in; Z-axis: 22.5in

The weight is going to be approximately 338lbm.

The nominal design loads for this unit is presently just a load in any direction of 300lbf. This is a rough value sampled from estimates of peak tool tip loading on the configuration while being used as a mill. The 300lbf should be higher than the loads experienced and we will likely slide compression load cells onto the setup to extract in-service loading to refine that 300lbf to some lesser number. the 300lbf figure also helps in understanding the min required torque from the motors to hold the axis steady and the tool tip deflection expected in-service.

paneled table top

I bought a patio table some time ago and I realized the tiles used on the top are all 12in x 12in and there is a decent amount of space below each tile. This setup is perfect for creating an interchangeable table with panels that can swap in and out for different functions. The image I have of the model has a flower pot insert shown and a propane tank shown below the table. I can’t take credit for the flower modelling or the propane tank itself (those were open source models) but the rest of the design was reverse engineered from the table in the photo. I still have a little bit of work to do to get the model closer to the actual design but in the region near the tiles it is representative of the space available. From the design it seems like the propane tank would be a pain to roll under the table and hook up to a grill tile so I’m going to have to rethink how to do that.

3d printer printed Enclosure

The first attempt for the printer enclosure was supposed to be easy in the sense that all parts could be ordered already cut to size and ready for assembly. I don’t have a lot of space for manufacturing equipment in my apartment so I can’t leave a lot of parts requiring much more than a wrench or 3d printer. I noticed in my price break down that the costliest parts were the transition components but if I was able to print the full structure, then I might not need the 8020 at all. I detail some of how I came up with an equivalent structural component in my blog.

The images show some of the sections I created for a polymer equivalent. Unfortunately, the cost of the polymer to match strength of the aluminium resulted in a more costly part than just buying the junctions or straight sections. I’ve come to the realization that the enclosure could be made using steel angle bar and 0.030 thk mild steel sheet for something around ~$500. I will post the design in a separate entry when I have the design completed.

3d Printer Enclosure

Its pretty well known that moisture absorption of 3d printer polymer causes popping of the filament during extrusion. Some of the consequences are interrupted extrusion or poor surface finish. Furthermore, I found that my build plate was having difficulty getting above 200F for printing ABS plastic. I have been able to do PETG, but was hoping to be able to do ABS with some more established engineered strength properties. The solution to both problems is to control the environment more closely. The enclosure will limit the convection bled to the room in the house and confine the heat to the volume of the enclosure and a Honeywell BME280 sensor, arduino, and either desiccant packets or a mini dehumidifier will control the issue of moisture. The images of the model resulted in a cost of about $1,000 for just the 8020 items not including the cost of the panels. This is a bit steep so I’m going to try to cut the cost.

Hanger of Hangers

My girlfriend showed my a space saving as-seen-on-tv hanger of hangers. I took a look at the basic design and put together this 3 piece assembly. It takes around 12 hours to print one assembly. The design is printed in 3 segments and the hook ends are pressed into the holes on the bar hanger section. A pretty simple concept and considering a pack of these goes for like $18 its an easy savings to just print them. The one downside being the 12 hours it takes to print. I have yet to have had one of them break on us (I suppose that statement is asking for problems though)...

dampener

I started getting complaints that my printer was too loud at night so I threw together an elastomeric dampener shown to the left. I don’t even have the model anymore, but it was a pretty straight forward model. As can be seen, the print quality was marginal, but once mounted, it was still able to significantly cut down on the noise from the stepper motors. Part of the problem was also the non-rigid table top I had it on at the time.