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Rotary machining a statue (Venus, Nefertiti).

Two beautiful woman (Venus de Milo and Queen Nefertiti of Egypt) are used to show you how rotation axis machining is done in DeskProto, in the printed tutorial and in the video tutorials.
- In Lesson 3 of Tutorial book you can find detailed instructions about rotation axis machining.
- The Video tutorials can be started below:
A note about rotation axis machining: in case you cannot select "Use rotation axis" as that option has been grayed out, you need to add rotation axis support in the definition of your machine in DeskProto: Options menu -> Library of machines -> OK on warning -> Select your machine and press Edit -> Press "Advanced settings" -> Check "Has rotation axis" and enter a value for Distance to working table.

1. Venus de Milo geometry

DeskProto screenshot of the head of the Venus de Milo statue
The geometry file has been created by 3D scanning the Venus the Milo statue (Louvre, Paris)

The Venus STL file is available for you to download and use it for training purposes.
The file is an 3 MB file, containing only the STL file. Some background information on this geometry can be found on the gallery page about this statue.

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2. Venus, rotation axis toolpaths video

Creating toolpaths for rotation axis machining. Continuous rotation: the model rotates during machining, like a roast on a barbecue spit   (16.5 min)

The Rotation axis tutorial video teaches you how to create rotation axis toolpaths in DeskProto.

These videos do not apply to the DeskProto Entry Edition and Expert Edition: rotation axis machining is not possible in these editions.

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3. Venus, rotation axis machining

Video that shows rotation axis machining, using the toolpaths made in the previous video   (6 min)

The Rotation axis machining video shows he machining of a Venus model, using the toolpaths created in the previous tutorial video.

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4. Nefertiti: advanced topics for rotary machining

Advanced topics for rotation axis machining. Including a download link for the STL   (32 min)

The Nefertiti tutorial video tells about the "Nefertiti hack" and then teaches you about these advanced rotary topics in DeskProto:
  • Combining rotary with plain XYZ
  • Custom support tabs
  • Dealing with undercuts
  • Waterlines for steep surfaces
  • Dummy operations
  • Chaining a number of operations
  • Safety position while rotating
These videos do not apply to the DeskProto Entry Edition and Expert Edition: rotation axis machining is not possible in these editions.

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5. Results showcase for the Venus statue

Machining Venus, on an Isel desktop CNC milling machine
The resulting small Venus sculpture
A small sculpture in PUR foam, 75 mm high

These first two pictures show machining a small version (75 mm high) as described in the video tutorial. The model is machined in dense PUR foam, on the Isel CPM desktop milling machine in our own workshop. On the picture left you can clearly see that a next layer of material is being removed: roughing.

Large Venus sculpture in a car
Large Venus sculpture on exhibit at a trade show
And a big sculpture in PS foam, 65 cm high.

The second Venus is much larger: more than life size (65 cm high). This version has been machined by Komplot Mechanics, on their large Dynamight CNC milling machine. They often work with simple expanded PolyStyrene foam (the type with the small beads) because that is cheap and they need large volumes.
On the picture left this Venus is on her way to the Euromold show, right she can be seen while guarding the DeskProto booth at that show.

Three views of a small Venus model in brass
A small model in brass. Note the text that is wrapped around the base of the model

In contrast, this Venus model is small: only 36 mm high and 18 mm wide. It has been machined by trial version user Thien Luu of Thien Quynh Trading & Producing Company in Ho Chi Minh, Vietnam: thanks for sending these pictures !
The model has been created on a Thien Quynh machine (the company is a machine builder), using three different cutters: Roughing: flat tip D 2 mm - Finishing: ball nose R 0.5 mm - Engraving: conic tool 45 degrees.

Venus being machined in brass
TwoVenus sculptures in brass
Left on the machine, right two results.

DeskProto user Mauri Romano and his brother (Australia) also use brass for their sculptures. They milled the Venus statue on a four-axis X3 Milling machine that has been converted to CNC. Specifications: X and Y 2000 mm/min, Z and A 1500 mm/min, air cooling on the tools. It has two spindles: one goes to 4000 rpm and the other 24000 rpm air cooled. The machine uses the Mach3 control software. They have also built a larger CNC router table, which will be used to machine wooden sculptures.

Mauri and his brother have used Venus to get started with sculptures. Mauri says "We have made many other 3D models in Brass and Wood, we also have many more planned some of which are very complex 3D STL sculptures".
Note the color difference of the two statues above, which comes from the finishing: both are in brass, the left statue has been blasted with fine Garnet stone powder ("sand"-blasting), giving the brass an aged look.

Venus after roughing toolpaths
Venus after finishing toolpaths
Venus after all milling
Venus after polishing
Venus in brass: four stages during the process

The four pictures above show four stages of the process. All pictures courtesy of Mauri Romano.
He says: To produce the above pictured statues we did the following. We used a 25.4 mm diameter brass rod, held in a Rotary table chuck on a small CNC mill, using Mach 3 operated controller. We did all dry cutting using carbide cutters with air cooling.
  • Leftmost the roughing toolpaths. Roughing cutter 3.125 mm diameter ballnose.
    Meander cuts, parallel around A, at 650 mm/min, 1.5 mm roughing layer height and 0.464 mm steps. Roughing skin thickness 0.07 mm. For all operations the max spindle speed of 24000 rpm was used. All X movements and Z cutting plunges at reduced feed. (23253 Lines of code, machining time 4 hours).
    Note that the picture shows an error model: too much material was removed at the neck due to an incorrect setting in Mach3 (for more information see the DeskProto FAQ).
  • Next the finishing toolpaths. Finishing cutter 0.79375 mm diam, 2 flutes ballnose.
    Meander cuts, parallel around A, at 650 mm/min, 0.02 mm (!!) steps. (1543086 Lines of code 14 hours 20 min).
  • Third picture is after machining the base (sockle). Roughing cutter 1.5875 mm diam, 2 flutes ballnose.
    Meander cuts, parallel around A, at 650 mm/min, 0.161 mm layers and 0.318 mm steps. Skin 0.05 mm. Z plunges reduced to 270 mm/min (8552 Lines of code 2 hours 30 min).
    Finishing the base: Engraving cutter 30 Deg, tip diameter 0.1524 mm.
    Meander cuts, parallel around A, at 650 mm/min, 0.046 mm steps. Z plunges reduced to 270 mm/min (13935 Lines of code 3 hours 20 min).
  • Rightmost after finishing to high-gloss
Finishing has been done in two steps. First stoning by hand using fine fast breakaway stones to remove all the tool scratches. Next the model has been tumbled in a small drum with Garnet stone powder 600 grit to produce the shine. Finally a fine spray of lacquer has been applied.

Venus sculpture in wood, roughing
Venus sculpture in wood, finishing
Milling in American maple wood: Left roughing, Right finishing

This Venus sculpture in wood has also been machine by Mauri Romano and his brother. It has been made from 103.5 mm diameter American maple wood (the largest diameter their machine can handle).
Roughing was done using a 11.1125 mm ball nose cutter, with feedrate 3500 mm/min and spindle 15000 rpm. Next the finishing cut, using a 3 deg tapered ball nose cutter, 3.175 mm diameter (1/8 inch). Feedrate was 3500 mm/min and spindle 23500 rpm.

Venus sculpture in wood, after milling
Venus sculpture in wood, final result
The oil treatment makes a big difference

After machining the support tab at the right side was removed manually. Finally Venus was treated with a Coat of Tung Oil, resulting in this beautiful work of art.

Venus being machined in brass
YouTube screenshot
Left a photo, Right a video on YouTube

The next Venus comes from India, and is made by machine manufacturer N-Gravetek in Nashik.
N-Gravetek emailed: "Last month we downloaded the evaluation version because we got a machine enquiry from a model sculpter artist. We did one sample demo job using the deskproto evaluation version, the sample job picture done on our machine is attached herewith."
Not bad at all for a first test :-)

Venus statue in POM plastic
YouTube screenshot
Bert's Venus in POM: the result and on the right a video showing how it was machined

This plastic Venus is about 65 mm high, machined in POM by Bert Eding, as a demo for the EdingCNC control software that he manufactures: Eding CNC in the Netherlands.

Both roughing and finishing were done with a 3 mm ballnose cutter, applying a roughing skin of 0.3 mm. Finishing was done with strategy Parallel, around A-axis reversed. Important was the milling direction: conventional was needed for a good surface quality in POM. Toolpath distance 0.09 mm, for a very smooth result.

Venus statue in Abachi wood
Venus in Abachi wood, in front of the EAS machine on which is was milled.

Abachi is a great wood type for machining: a fine grain and a smooth resulting surface.
This Abachi model has been created on an EAS machine, by Dutch reseller NC Techniek. Here roughing has been done with a 6 mm diameter ballnose cutter, finishing with a 3 mm ballnose.

Venus statue in EPS Styrofoam
Venus in Styrofoam, made on a special purpose foam miling machine by ESP Muhendislik.

ESP Muhendislik in Bursa (Turkey) manufactures special machines for Styrofoam (EPS, short for Expanded polystyrene). This 60 cm high Venus is a nice example of what their machine is capable of.

Email us a photo of the picture frame that you created so we can add that to the list of results !
(in case you want with a link to your website).
It will be interesting to see which machines are used, which cutters, and also which fixtures for three sided ring machining.