Redback CNC

Some news!

There will shortly be a new CNC machine (CNC router) on the market.  Once that is Australian designed, and made as well.

Comes from a pretty interesting stable too – the same inventor behind the Torque Workcentre, and his company, YAS Engineering.  Now Keith (for those that don’t know) is actually a specialist in CNC machines, and has been making custom builds for years from the small, to the very large.   This design is one for production, rather than custom builds, and it is only about 6 weeks or so away from making the transition from prototype, to the first production machine.

And that machine will be making its way down to sunny Melbourne, to a modest shed that I am somewhat familiar with!

The bed on the CNC is 600x900mm, although the overall cutting capacity of the machine is more than that (yes, more, not less).  That means it can work over the end of the bed, so working on the ends of boards etc will be possible.

Thinking Aspire would be the best product to get to really showcase the capabilities of the machine, rather than just sticking to VCarve.  Have played with VCarve already, looking to jump to the next dimension (the third dimension) with my CNC routing!

More news as it comes to hand!

 

Natural Art

Sometimes a piece of timber catches my eye, and although at the time I have no idea what it will be used for, I grab it and store it until it has a chance to tell me what it wants to be.

It has been like this long before I had any decent tools (or skillset) to actually do with the piece what it wanted to be.  Many would argue that the skillset is still lacking, and I’m not going to argue with you on that score!

One such piece was at a woodshow a few years back.  I probably blogged about it at the time.  It was a slab of camphor laurel, and it has been sitting in my wood store for a few years now.  It was always intended to be a coffee table or some such.

I have just received the surfacing/spoilboard bit from Toolstoday.com, and it was a great opportunity to put the bit through its paces, and to make something from the slab itself.

To the bit for a sec (and I also shot a video of it all, so that will be up soon).  It was called a spoilboard bit, which is not a term I was familiar with.  Turns out (from a Google search), that it is basically what it sounds like, and comes from the CNC world (but machines in the serious spectrum).

These CNC machines utilise MDF as a base material, not (just) because they are flat, but instead because of their porosity.  If you have ever tried to use a VacClamp on MDF, you find it is very difficult to maintain a vacuum, until you seal the surface.  These CNC machines work the other way around – they pull a vacuum right through the MDF, to clamp the material to the MDF surface.  The rolled outer surface of MDF is therefore a barrier to this working effectively, so it needs to be machined off, and that is where the spoilboard bit comes into its own.  Spoilboard – which is as it sounds, another term for a sacrificial board, or base.  Not unlike how we use MDF on the Torque Workcentre.  Doesn’t matter if it gets cut into – it is designed to be used, and eventually replaced.

The same cutter is also perfect for slabbing, and that is how I primarily intend to use it.

It is a different design to other surfacing cutters I have come across.  They all have the vertical carbide cutters (either replaceable or not), which have a scraping action, but this cutter also has two cutters positioned on the base, creating a shearing action across the surface as well.  It is also a monster of a bit, at 63.5mm diameter! (2.5″).  This is not a bit for handheld work!

With either a CNC machine, a Torque Workcentre (or other slabbing setup), this bit will work to flatten a large area quickly.

I’ll have more detail of the setup in the video.  The slab was secured down, and with a number of passes, the surface flattened.  The bit handled some substantial cuts – at one stage it was cutting over 5mm deep across the majority of the width of the bit, and didn’t notice or complain in the slightest.  I’m sure it could handle even more, but I wouldn’t deliberately push a router bit to its limit.

Once the slab was flattened, a quick burst with the Festool belt sander, then onto the ROS with 80 grit paper.  Both these steps took next-to-no time – as you’d expect.  I didn’t have time to finish sanding (up through the grades), but wanted to at least see how it would look, so rubbed some Danish oil over part of the surface.

Talk about “POP”!

When whomever it was cut the slab, they were particularly frugal, and it was very thin to start with.  With the amount of resulting twist/warp, the slab was very thin in some sections (down to about 10-15mm).  Too thin to make a generous table.  However, the timber was already telling me it didn’t want to be a table anyway, and instead wanted to become a piece of natural wall art.  Who am I to argue?!

So I will finish off the sanding, then oil it right up, before mounting on the shed wall.  The only decision now, is which wall of the shed to use!

 

Time to don those 3D glasses

We are moving into a new dimension.

CNC machines are not restricted to 2D patterns and simply cutting in to produce a raised (or recessed) pattern.  Nor are they restricted to 2.5D, which is how patterns that are cut in 2D then built up to produce a 3D image are classified.

True 3D means the cutter is moving through all 3 dimensions as it is cutting.  This can still produce something like a bas relief image, but irrespective of how complicated, or simple the result, the motion of the cutter throughout the cut is the defining parameter.

Finding 3D patterns to send to the CNC machine are not as easy to find as I expected.  The 3D printing community openly creates and exchanges their creations, including the required files, and open source development programs, whereas the 3D CNC community charges significant fees for each and every pattern, and the software to develop your own costs $thousands.

I did download a sample file from VectorArt3D.com who also provide the code generator program (for free, but it only works with their files) called Vector Art 3D Machinist.  Bit of an experiment-was not sure if it would work on the CNC Shark, but it was fine.

The program produces the required G-Code for the CNC machine control program, but has an interesting additional output, that of a roughing out pass.

Given how much material the can be removed to create a 3D object, it is good being able to first run a heavier cutter to take a few quick passes to remove the bulk of material before the fine, final cutter moves in to refine the design.

Rather than just use any router bit to attempt to machine a design, I turned to the precision Amana Tool bits that are specifically developed for 3D CNC routing.  These come from Toolstoday.com, and are Zirconium Nitride (ZrN) coated router bits.  I know it says coated, (which to the layman suggests painted or dipped) but I suspect they may be produced using one of the physical vapour deposition techniques.  This is an important distinction.  A coating can rub off over time.  A vapour deposition has characteristics somewhat akin to welding, where the coated layer fully penetrates into the surface of the base material, effectively creating an alloy at the surface.  Localised, controllable, surface alloying is a particularly effective modern technique for producing exceptional products.

The bits are all up-spiral, pulling material up and out of the cut, while the cut itself is not a chipping action, but a slicing one.  They are particularly sharp, and smooth.

The first pass was a roughing pass, using the largest bit seen to the left here.  It quickly scallops away the bulk of material, leaving the finer router bits to produce the detail, without having to push through tonnes of material.

Once that pass was done (4 minutes), the bit was swapped over for the one making the final passes for detail.

The final result looks a bit rough – more refinement by me I think.  It is definitely not the router bit – the ZrN bits performed superbly.

Final pass, which was about 16 minutes for this size pattern.

The additional benefit of these router bits, is their ability to handle other materials, such as aluminum, brass, copper, graphite, phenolic composites, plastic, sign board, & wood.  The ZrN surface is particularly useful in preventing buildup of the material being cut, such as plastic and other gummy materials.

The benefit of having a set of bits is having the right ones available when you need them (and less costly than purchasing individually).

The set of 4 covers a good range.  If you are heavily into 3D CNC woodworking (and as a business), consider the 8 piece set.

The Boris Goldberg Kerf Chair

This is pretty cool – a chair created on a CNC machine using kerfing as the technique to give it shape.  Opens one’s eyes to all sorts of possibilities.

Woodwork Sayings

Was taking to Daniel at Carbatec earlier today, and after we started coming up with some woodworking sayings, he suggested it would make a blog post.

I’ve decided to take it one step further, and once a list of sayings is together, I will choose a number that I will combine into a file that I’ll then cut on the CNC machine.  I have a large piece of camphor laurel that may be good for the list, which I will then be able to mount onto the shed wall.

This is what I have come up with so far.  Some are traditional, some are slightly modified, and a few are my own.

 

Measure twice, cut once, buy extra just in case

You can’t do the job right if you don’t have the right tools

The success of your project starts with the right lumber

When you get to the finishing stage, you’re half-way there

You can never have enough clamps

I only hope when I die, my wife doesn’t sell my tools for what I said I paid for them

When asked when you purchased a particular tool, the answer is always “I’ve had that one for years”

A workshop is a tool like any other

A router is just a motor to spin router bits

It’s not a mistake, it’s a design feature

Use your sand paper as if someone else is buying it

RTFM

Get the board stretcher

Quality remains long after the purchase price is forgotten

 

If you have any others, please drop them into the comments, and I will compile a final list of my favourites to send to the CNC.

Plotting the End of Days

Given we are still here, guess that yet another “End of Days” has quietly slipped on past.  However, the Mayan calendar (or is it Aztec?) is still one of the challenging images that are sent to CNC machines all over!

I’ve been playing with this one today:

Mayan Calendar

It is quite a challenge for a CNC machine – results in around 1/2 a million lines of G Code to produce all the required cuts.  I started off cutting it into pine, but the initial size chosen (200x200mm), the depth of cut and the crapiata used, the results were not worth pursuing, so I cancelled it after about 45 minutes (so at least I could get a good idea how it could look).

Given how packed the garage is waiting for the new shed, working on a CNC machine is almost the only way I can actually manage any woodworking at all!  Note the precarious location for the laptop, so it is somewhat out of dust range from the router.

I then decided to find something more suitable, and this laminated electrical board was eminently suitable, given the lower layer is a significantly contrasting colour, so the pattern shows up exceptionally well.  Again, this was only a test cut on the underside – this was scaled to 300×300, and would have taken 4 hours to complete.  I stopped it after an hour, again as it was only a test, and a couple of settings I chose were causing some issues.

The other side of the board is a shiny surface, and should look pretty spectacular.  However, I plan to make it near the limit of size of the machine (a 580×580 calendar).  I didn’t start it today as I wanted to get a better idea of the settings before getting it underway.  It will also take 14 hours(!!), so I need to get some noise control in place before trying it on.  I might drop it back to 500×500, which will probably be closer to a 12 hour machining.

The CNC Shark range can be sourced from Carbatec, and seen in operation on Stu’s Shed 😉