From the recent video, here are a couple of images of the dragon, cut from acrylic, aluminium, corian, carbon fibre, brass, copper, MDF, ply and melamine (and the assembled dragon is acrylic and aluminium).
Just been to the aluminium merchants, and picked up another $600 worth of aluminium sheet, from 1.5mm to 6mm thickness for some upcoming projects.
Been looking at a few different materials as part of this exercise on routing (CNC) a range of alternate materials and surfaces. Had a closer look at Corian today, and while I was generally aware of the term, and the look/feel of kitchen benches made of the stuff, I didn’t actually know much more about it. While this is unlikely to be news to everyone, a bit more information about what this product is may be quite interesting. Not sure how I missed knowing more about it until now, but there you have it – can’t know everything!
Turns out it is around 50-50 polymethyl methacrylate with aluminum trihydroxide filler. To put that in more common terms, it is around 50% acrylic polymer, and 50% alumina trihydrate, which is a product derived from bauxite. Bauxite, as you may well know, is the raw material that is processed into aluminium.
Makes a lot more sense to me now why some people have been using it to make pens on the lathe! Probably makes a bloody good pen if the truth be known, look, feel, finish and weight.
While it can be thermoformed into various shapes, it can also be machined relatively easily as well. So I will be rather interested to see how it goes on the CNC, both in shaping, even 3D work, and engraving. A number of router bits in my CNC collection are rated to handle solid surface materials, including the 3D cutters. Think it will look rather interesting, and opens the door to combining it as another material in a mixed material project. Especially given its machinability.
Bit of a test day today (isn’t every day?!) Wanted to see how some new bits from Tools Today would go with the nested projects I have been working on recently. Today’s test was on a scary looking bit – but not scary because it was big and mean looking – quite the opposite.
This bit is super fine, and a whole 1/16″ (1.6mm) diameter solid carbide cutting tip. It looks way too fine and fragile to use, let alone in a CNC router! However, I wanted to see if it could work, as it is currently the largest bit that I have that will cut 3mm MDF and not create oversized, and therefore sloppy joints. This bit in question is the 45190 Amana Tool straight cutter – 2 flute, and is not up/down or compression.
Thought it would break in a heartbeat, but hoped not. Even so, I slowed the feed speed down to 50mm/sec.
The result? Not only did it survive perfectly well, it cut really cleanly, and did not have a tendency to try to lift or move the MDF around, even when the distances between components was at a minimum.
I’ll get more detailed views (and video) of the bit in action at another time. What I was left with after my testing was this fellow. The bit performed admirably – I’m sure they have a reasonably high attrition rate, but so far there have been no dramas, or casualties.
While I wanted to wait until the project was complete before showing it, I have just finished a mammoth step, so decided to share the progress.
Starting with a slab of American Walnut
Then, after 24 hours of solid routing on the Torque CNC
And a quick initial application of Danish Oil (as much to find where I need to do additional sanding), the result is starting to show some promise. (The gauges are only to test fit, they will not join the project until it is pretty much complete). The top station (the celtic design within a circle) is not just decoration, it will also be a clock. The gauges are all high quality German-made ones I bought from Carbatec.
Big push at the end coming – how unusual………
Using the same steps discussed in the last entry, I have taken a vector drawing of a Celtic Cross (created by “CarveOne” on the Vectric Forum), and produced a 3d rendering of the design.
This is the first time I have really tried using multiple paths on the same object.
The first pass was a roughing pass – used to remove as much of the unwanted timber as possible with a strong router bit, and higher feed rates to perform the task quickly.
For this I used the 46294 3D carving bit from Toolstoday.com It has a Zirconium Nitride (ZrN) ceramic coating, so this bit is also appropriate for routing in aluminium, brass, copper, cast iron and titanium alloy. It makes very short work of the camphor laurel!
The final design was then carved using the 46282 3D carving bit. This has a 1/16″ diameter tip, so can really get into the details. Even so, there is a bit that is even finer, if even more detail is required (with a 1/32″ round nose tip).
I was using these at around 80mm/sec.
Once the design was cut, I swapped over to a solid carbide 1/8″ upcut bit to first cut around where the gaps were meant to be inside the design, and then to cut around the outside, down to about 12mm deep.
For a sense of scale, the cross is about 300mm high, and 200mm wide. Straight off the router bits, there is no need for sanding where the carving bits have been. There is a bit of feathering on the outside of the cut out, but that is both a function of the timber, and insufficient router bit speed.
I deliberately didn’t cut all the way through the timber, so there was no need for tabs to hold the cut pieces in place.
To release the cross from the surrounding material, I turned the whole thing over, then ran a basic flattening profile on the back, taking off 2mm at a time with a surfacing cutter – using the RC2248 replaceable tip cutter.
Once this cut down to the required depth, the cross was released.
Each project presents different challenges, so I get to know more and more about how to use the CNC router effectively, and how to incorporate it as another workshop tool.
I had a look back at some tests I did on the CNC Shark using 3D carving bits – the finish I am achieving here is chalk and cheese compared to my early experiments. I don’t know if I can attribute it all to the platform, but having such a solid, heavy duty CNC router certainly is not harming the finish that I can now produce!
Had a young fella visiting with his family today. I know it was a waste of breath, but I had to ask him “Do you like dinosaurs?”
It’s like asking a human if they need oxygen to live.
So the answer was a given. But he wasn’t expecting what came next. I handed him a set of about a dozen different dinosaur plans, and suggested he choose one. After a meticulous sort and selection (he’s all of about 4!), one was chosen – a triceratops. Has big horns for hunting I think was the rationale.
No problem, let’s go make it. So first, camped out on the lounge floor we loaded the plans into the computer, fitted them to the board size (nesting), and set the required tabs.
Then it was off to the shed, with a small entourage in tow. While the kids watched, I set the CNC up for the job, explaining what I was doing each step. There was a board placed on the ground a short distance from the work area, and strict instructions that only I could step over that board. A small step ladder placed on the other side of the board was a very convenient lookout, and it was duly manned for pretty much the entire time.
As each board was completed (this particular pattern required three 900x600x6mm MDF boards) (and yes, dust extraction and air filtration were on), the entourage were involved in popping each piece loose, then each piece was duly handed to me one at a time so I could sand off the tabs on the disk sander.
The young fella was funny. He couldn’t get over that we were making ‘his’ dinosaur. Nor that it was going to be ‘big’. After all, what does ‘big’ mean to a 4 year old? A big toy is perhaps a foot long? Maybe? You wonder what they expect, although they are already processing the concept of limiting their expectations so as not to be disappointed. So ‘big’ is relative, especially when compared to all the other toys that receive the same description. He kept asking what I was doing now (or more specifically, what the CNC machine was doing now). He was confused that even after a number of parts were cut, we were still making components for his dinosaur. Again, you could see it was already exceeding any preconceived notions of scale.
With the pieces cut out, we traipsed back into the house, where the dinosaur was assembled.
That is when eyes got really wide. Followed closely by a most impressive grin!
All up, took at most an hour and a few sheets of MDF, and that was about it. Sure beats those tiny 6″ long models made in China that keep appearing in pop-up shops in the various malls. Nothing is better than a ‘serious’ dinosaur. Especially one that redefines the concept of “big”. Better than oxygen.
Plans from MakeCNC