After spending a few years and countless projects with my first CNC router build I have decided its time to fix the major issues I encountered.

The main issues with the original build
- Machine base was not big/strong enough in relation to the gantry size/weight
  • Under high acceleration/deceleration I can visually see flex in the base when the gantry stops

- X axis motor mounts and ballscrew mounts where not properly braced for the loads
- Epoxy leveling
  • The epoxy leveling worked to within a 5-10 thou for flatness but with no rail reference relying on clamp torque on rails not ideal for such a large gantry
  • No bearing block reference edge on the gantry feet

- X axis rails not full length
  • Original rails purchased used to save money, without proper rail reference it is difficult to keep rails properly aligned. Blew out a bearing block when it caught on the misalignment.


These items above can be mostly worked around by slowing the machine down considerably. Original design should have had the machine at ~2000ipm rapids with very snappy accel. I have reduced to 1000ipm for rapids and rounded off the accel considerably.

The NEW machine
- Base material size considerably larger than original
- New Gantry larger legs with better feet bracing
- Integrated vacuum hold down plenum
- Still 5x10 machining area
- Still 18 inches under spindle nose (no tool) when fully up
- Small wood storage under machine (I keep my rough board stock under current machine)
- Steel structure stress relieved
- All linear rail and block locations machined with reference and rail lock provisions
- All drive and motion components to be moved from current machine
  • except X axis rails, new full length 30mm rails to be purchased for new machine


Current machine motion parts to be moved
- X axis
  • Full length 25mm x25mm lead ballscrews
  • Dual 1 kW Servo motors
  • **New 30mm Hiwin Rails

- Y Axis
  • 20mm x20mm lead ballscrew
  • 0.75kW servo
  • Schaeffler Linear Rails 25mm

- Z Axis
  • Entire Z axis will be moved over to new machine
  • Current Z consists of 20mm x20mm lead ballscrew, Schaeffler 25mm rails, 0.75 kW servo, 10hp Coulombo ISO 30 Spindle
  • New Z to Y plate to be machined to account for larger Gantry


Design
I started designing the base and gantry over Christmas break trying to optimize strength and cost. I then came upon a deal on some large section box tubing at scrap cost so I redesigned around it. The box tubing is 10x10x3/8 inch and 8x8x5/16 inch the design below was optimized for this material.

Photos Attached of Design - Having trouble putting them inline