CNC Router

The CNC mill without spindle. CNC Mill.

Description

We currently have a under construction C BEAM based CNC Mill. The mill took its first cut on 20/02/2016.

The CNC Mill is based on the C BEAM profile from open builds, it is currently a X/Y table type "C BEAM MACHINE" thats 400x400x120mm but we have all the parts to make it a 1000x750mm gantry style ASAP.

To use the machine you have to be inducted, and before then you should be familar with CNC Mills (read the CNC Mill Guide); it is also a numerically controlled power tool with a variable Z and so considerable care should be taken in preparation and operation.

Please see the CNC_Mill/Feeds_and_Speeds page for information on the kind of cut settings you can use on the mill when setting up your CAM.

Once you have a valid Gcode file from your CAM package, you will be able to use http://chilipeppr.com/grbl whilst at the space to run your file on the CNC.

Specifications

• 800W water cooled spindle 220V 6.5A with ER11 collet
• 1.5kw VFD capable of 3000-23000 rpm
• 3.2Mn NEMA 23 steppers
• 36V Stepper power supply
• 2.5A Stepper drivers
• Control via GRBL running on a arduino screw terminal sheild
• Raspberry PI serial to JSON server making the CNC shield available on chillipeppr.com when at the space.
• 325x250x100mm workspace
• No load max feed of 5000mm/min
• 6 x Capacitance 6-36V end stops

Configuration

Here is the basic configuration of the machine to judge it against others you may see.

GRBL

The CNC uses G code parsed by GRBL. Send the command $$ to GRBL to read the current configuration. This should not be changed unless something significant changes with the machine.

• Homing is enabled
• Hard limits are disabled
• Soft limits are disabled

VFD

The spindle is controlled by a VFD. The current configuration settings can be found on the VFD page.

Drivers / Motors

Drivers are TB6600's 'capable' of 50V 5A

• 1/4 microstep mode
• Full power
• Supplied with 36V

Motors are 3.1Nm Nema 23

• Wired in series mode
• [Datasheet]

Build notes

The end stops are wired as follows:

1 - Positive 2 - Gnd 3 - Signal 4 - Signal

Experimentation is required to determine which detector

Pledges

A pledge tracker can be found on this google sheet [1]

Design

The first machine is a 'out of the box' C Beam Machine kit [2]. This is a X/Y table machine based on the C Beam aluminum profile which offers better stability and accuracy than OX type v slot or shapeoko.

This kit will be used to make the plates for its own upgrades into our specific 1000mm x 750mm gantry style machine with dual X drive based on this design. [3]

Parts Status

We have purchased the majority of parts from Colin at robocutters.co.uk[4], he offered a wealth of advice, a great discount and is genuinely interested in supporting Hackspaces.

• A C Beam machine kit
• 3 NEMA 23 Motors
• 1 1000mm linear actuator kit
• 1 750mm linear actuator kit
• 4 750mm 60 aluminium profiles
• 16 wheel kits

From China we ordered as a kit:

• 800W 60mm mount water cooled spindle
• 1.5kW VFD
• 12 VPump
• Various collets

From other sources:

• 6 C.P type limit switches (swwils)
• Radiator (swwils)
• 4 Core spindle cable (swwils)
• RUMBA Board + Drivers (Martyn)
• E-stop (Aidan)
• Arduino CNC sheild (swwils)
• Arduino UNO (swwils)
• 36v 10A PSU (Aidan)

Parts needed

• Cable chains (larger machine)
• Regular stop / go button

Build log

• First cut occurred
• Limit switches installed.
• Hard limits set
• Soft limits set (but broken!)
• Dir inversion issues (0,0 should be lower left?)
• Dir inversion worked out (its actually correct to set machine into negative space)
• TB6600 Stepper Drivers Installed
• Wasteboard installed
• Some hold downs installed
• Machine tightened and thread locked (blue)

Upcoming

• Writing documentation
• PWM spindle control / enable

Software Proposals

GRBL vs TINYG [5]

CAM [6]