08. Computer controlled machining

Tasks

group assignment: • do your lab’s safety training • test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine individual assignment: • make (design+mill+assemble) something big (~meter-scale) extra credit: • don’t use fasteners or glue • include curved surfaces • use three-axis toolpaths

Outline

remove material using a defined cutting edge (chips)

Machines

Tooling

Feeds & Speeds Toolpaths

Class

Assignment

Completing this weeks task of making something big, whilst also considering the logistical challenge of transport back to the UK, resulted in the design of a sink cabinet to be fitted into a van. Over the last 18 months a friend has been converting a ford transit into a camper van, which I have been more than happy to assist with! At present the van (daisy) has been fitted with flooring, walling, bed frame, solar panels & a air vent. ‘Daisy’ is almost ready to hit the road this summer, where she can be driven to Spain to collect her water management system.

Ideation

Initial sketches of the sink cab, showing hight of sections & positioning of components such as the water containers, along with a floor plan showing the units placement within the van.

Key dimensions (h x l x w)
 > 2x 10L water containers - 340 x 135 x 280mm
 > Sink - 145 x 420 x 30mm
 > 10L pump - 105 x diam 38mm (sits partially in 1 water container?)
 > Tap attachment - diam 22mm

Concept

Development of cabinet considering driving dimensions & component sizing. This was set up in rhino using rectangles drawn on the front / top plane to extrude 10mm sheets. I then created a cube a placed it central & aligned with the top plane, to create the sink this cube was shelled (top plane removed) then Boolean intersected with the top work surface to create the sink insert

Implementation

I have been helping a local business owner to set up the CAD models & toolpathing to CNC cricket bats. Whilst the initial profiling & model building was simple, the manufacturing is proving more challenging as the post processor needs setting up & the machinery isnt standard. As the tooling & machine set up wasn’t avalible as a download into fusion, I built a simple mock up of the CNC environment comprised of a planer spiral cutter (xyz) & a rotating jig to turn the bat (a axis rotation). The CNC has 4 axis and is based on a schnitzer nero CNC lathe & uses a Pocender control system

Tool

4 tangent arcs to create a flute, diameter 62mm, length 140mm circular array x6 sweep vertical rotate 30 degrees

Rotary JIG

Built jig using extrude, created lane from face to create cuts & chucks (mirrored) Saved bodies as components and assembled with stock block (stand in sizing) RH Face of stock & RH Chuck small face had rotary joint applied. Added drive motion to this so angle can be adjusted

Machine Set Up

In the machine library I selected to edit a ‘generic fusion cnc lathe’ that had been copy/pasted to my local library from the fusion library. In the machine definition window, under the ‘model’ tab I changed it to the rotary jig & entered machine builder mode. After playing around I couldn’t get it to work as I didn’t have the right components to be able to assign axis & movements, so I further built out the machine around the cutter tool where movements can be applied to.

post processor

searched fusion library & copied into my local library Fanuc, Mach3, GRBL (suggested as Pocender isn’t supported)

Key Words

Chips : Flutes :

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Notes

Page 72/73 04/03/2026 Wednesday Lecture CNC & CAM

Tom Bodett Tony Schmitz

Cutting tools subject to wear from forces, temp, speed • Calculating forces on tool face exerted to material ok (chips)

• Tool types & materials e.g. carbide, HSS. Solid or bits • Machine types (turning, milling) • Axis & rotational planes • Tooling flutes/teeth, end types & applications
• machine parts

• climbing up /down results finish • Feeds & speeds effected by material, end types, Wood Grain direction etc

• CAD & CAM define & toolchain e.g. post processor to Control/command - Post processor used for speific machine calibration

• Work coordinate system tells you where the part is located in space (OPs?) - machine & work coordinates using work offsets • use planes to move cutter to part location • Workholding - Vacuum, Veeholder, jigs, clamps, tabs • Safety - Hear, Smell, See • Joining, Fixtures, Finishing - PVA, epoxy - Screws, bolts

4 by 6 wood OSD