CNC Router

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The CNC mill.
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; it is also a numerically controlled power tool with a variable Z and so considerable care should be taken in preparation and operation.

Specifications

  • 800W water cooled spindle 220V 6.5A with ER11 collet
  • 1.5kw VFD capable of 3000-23000 rpm
  • 3.2Mn NEMA 23 steppers
  • 20V 4 A power supply
  • 2.5A Stepper drivers
  • Control via GRBL running on a arduino CNC sheild
  • Raspberry PI serial to JSON server making the CNC shield available on chillipeppr.com when at the space.
  • 400x400x120mm workspace
  • No load max feed of 5000mm/min

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.

  • X steps/mm = 200 (1/8 microsteps)
  • Y steps/mm =
  • Z steps/mm =
  • Accel X =
  • Accel Y =
  • Accel Z =
  • Max Rate X =
  • Max Rate Y =
  • Max Rate Z =

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

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]