CNC Milling Machine Vote

Sponsors

• Elizabeth Koprucki, CNC Area Host
• Dean Anderson, Cold Metals Area Host

History

• Announced: 11/5/2014
• Language lockdown: TBD
• Vote date: TBD
• xx yes, xx no, xx present

Background

Our CNC machines are among the most popular tools in the space, but are not suitable for machining tough materials such as steel and cast iron and are limited in their ability to machine non-ferrous metals. While our current Bridgeport milling machine can work with tough materials rather well, it is a manual machine which makes intricate parts tedious and sometimes impossible to produce.

For industry, aging electronics often makes older CNC machine tools obsolete before the mechanical parts wear out. These machines can be inexpensive and if mechanically sound, are good candidates for electronics retrofits. Replacing the CNC controllers provides the reliability and features of a modern machine at a small fraction of the cost of a new machine.

This proposal is to buy an older CNC milling machine in good condition and replace the majority of the electronics with modern parts. This will likely include the motor drivers, rotary position encoders, and CNC controller. Depending on their condition, we will try to reuse the motor power supply, switches, spindle and axis motors.

Candidate Machine

We have located a Bridgeport Series I Interact machine that we believe would be a good machine for our shop. It is very similar to our current manual Bridgeport with a few exceptions:

• DC servo motors controlling x & y axes and the quill.
• automatic oiler
• quick change spindle (not R8)
• old Heidenhain CNC controller
• 34"x12" table (shorter and wider than our Bridgeport's table)
• ball screws instead of Acme screws for x, y, z axes.

This is probably a mid to late '80s machine, newer than our manual machine. Overall, the condition seems to be at least as good as our Bridgeport. The chrome ways have little wear and there are no marks on the table.

Software

The possibilities for controller software, in order of preference, include MachineKit, Linux CNC, Mach (4 or 3). MachineKit and Linux CNC are open source. For CAM, we will use our current Aspire software.

Computer Hardware

Unless there are unforeseen obstacles, the CNC controller will be a Beagle Bone Black running MachineKit.

Location

The CNC Milling Machine will be located near the Bridgeport milling machine, as they will be able to share tooling and this location is convenient to 3 phase power, which is required by the spindle motor.

Costs

• Milling Machine $1000
• Sales Tax $65
• Delivery $150
• Vise $150
• Control computer, monitor, keyboard, mouse $250
• 3 axis motor controller $400
• tool holders $150
• 4 rotary encoders (1 per axis plus spindle) $120
• miscellaneous (wire, hardware, etc) $200

Total: $2485

Total

• Actual Total: $2485
• +10% buffer: $2734

Language

Authorize the board to spend up to $2734 of Spaces funds on a CNC milling machine, rigging costs, controller upgrade costs, etc. Authorization expires 6 months after the vote is accepted. The expenditure is to be executed so long as there are more than 8 months worth of rent in savings.