cnc milling Archives - Page 13 of 14

December 20, 2017June 30, 2020

Ratchet Wheel Trial Cut using Gearwheel Designer

I am now running Version 21 of Gearwheel Designer and it gets better all the time.

I decided to make a ratchet wheel as my next test. This highlighted the need to think about the process order on the mill. Below is the design image in Gearwheel Designer.

My CNC sequence was as follows : –

Cut the square brass blank a little oversize and draw a diagonals on it to show the nominal centre (Manual operation).
Drill four holes in the corners outside of the working area of the cutting and use these holes to fasten down the blank to the milling table (which I had protected with a piece of MDF). (Manual operation)
With a drill bit as appropriate, drill radial holes in the centre of the spoke petals and also the centre hole.
Fasten the petals down to the MDF using these radial holes.
Cut the gash outline of the wheel.
Remove the four corner screws and remove the liberated brass outside the gash cut.
Cut the rough pass on the teeth.
Cut the fine cut on the teeth.
Fasten down the periphery of the wheel with small clamps.
Gash cut the spokes to leave the petals free from the blank.
Remove the screws holding the petals and remove the brass liberated.
Run the final cut on the spokes.
Job done apart from a light sanding to remove any small burrs.

Some more images follow : –

Gash cut done and teeth cut twice round. The clamps are in place holding it down while the petals are cut.

Petals cut and removed for the final cut on the crossings

The purists will now tell me how it isn’t a proper wheel because the crossing interfaces to the rim have radius rather than a sharp corner.

Well a file will soon fix that …. and I can tell them how I watched another three episodes of House of Cards while this wheel was being cut.

Similar or related subjects : –

November 5, 2017June 30, 2020

Delph Gearwheel Designer clock wheel design software

I came upon the Delph site and was excited at the possibility to cut clock wheels on the Tormach PCNC440 as this was one of my prime motivations for the purchase. Does anyone love crossing out wheels ?

Delph has been feeding me with updates to their code and it is starting to make sense what it is doing and I like it. Today I have run a wheel on slightly hybrid code (Delph plus my direct G Code hacks) and I am impressed so far.

The Delph code lets you design all manner of wheels for clock and other applications. You can define the style of the teeth, the crossings etc and you can drill or mill arrays of holes. You can also define the order of the machining processes. I bolted down a square of brass with corner holes holding it down – you can see the holes in the MDF below. Next I had the Tormach PCNC440 drill the three sets of holes in the blank, then cut the blank to circular size to match the teeth maximum diameter. In the picture the mill is cutting a rough cut first pass on the teeth using a 0.7mm carbide cutter. Next is the tooth fine second cut and then I can cut out the crossings which is what the five screws are for – holding down the petals that will become free once profiled.

It is all in 2.5 D but well worth a look.

http://www.delphelectronics.co.uk

Delphe GearWheel Designer Tormach — First wheel tooth being cut using the Delphe application.

Update : –

All went well in the first rough pass on the teeth called a Gash Cut in the software. I was running at 4000 RPM and 5mm per minute and each tooth was taking 4 minutes with a slow 3mm lead in. The second finishing pass was much quicker and now only leaves the crossing out to run. As each petal of the crossing out is cut free , the screws shown above will keep the petal segments in place so there is no damage to the tooling. I have made some small clamps on the 3D printer to put around the outside of the teeth to keep the wheel in place and centre screw to hold once the petals are cut free.

Gearwheel Designer, Tormach PCNC440, Fusion 360 — Clamps in place ready to run crossing out

Crossing out completed and milling finished

What a feeling to complete it and thanks to Delph for their support in getting me there.

See some more details and screen shots here.

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October 26, 2017February 19, 2018

First Ding on the Tormach PCN440

Well it had to happen …. first ding on the Tormach 440 which thankfully was not major.

I made a spring loaded pen from an old Parker Pen body and refill to allow me to sketch the XY movements of the mill on sheet of paper on the mill table. I forgot to reference the tool lengths and the pen buried itself into the table …. fortunately I had a sheet of MDF fastened to the table for protection but the pen dramatically disintegrated and distributed itself around the workshop.

A new pen has been made, better than the first one and no damage to the mill, just to my pride.

I must practice hitting the STOP button with my eyes closed.

First trial cut on Tormach 440 using Fusion 360 CAM

After a lot of research and testing I managed to run a small test piece in MDF using Fusion 360 CAM imported into the Tormach 440. Hand hovered over the emergency stop button but all went well. Getting there slowly.

There are so many boxes in the CAM settings for each function that is a worry what needs ticking where. Lars Christensen‘s Part 4 video on CAM helped no end. The other one to watch that was useful was the Library tutorial.

Battery replacement module for Chinese vernier scales

When I created the external 1.5V PSU modules for use with my DRO350 it struck me at the time it might be possible to create the same PSU in a dummy battery to fit directly into the scale battery socket.

I used the same AMS1117 regulator chip and decoupling capacitors mounted on a small pcb inside a short piece of K&S thin wall brass tubing. The pcb was milled on the Tormach 440 with hand written G Code and using a dental burr as the engraver. Once the pcb was soldered into the end of the tube I turned back the tube to leave the pcb proud of the tube to match the normal battery profile and spring contact in the scale battery socket.

It was a bit tight to put together but it works ! I am debating a full write up so look back in the future.