DIY CNC MACHINE

I’m a mechanical manufacturing engineer, a passionate advocate for hands-on learning and the endless possibilities of DIY projects. For me, it’s not just about building things; it’s about exploring, problem-solving, and pushing the boundaries of what’s achievable. With experience in vocational training, I’m excited to share my knowledge and inspire others to embrace the transformative power of DIY.

Building a DIY CNC (Computer Numerical Control) machine can be a challenging but rewarding project. CNC machines are used for a variety of tasks, such as cutting, engraving, and milling, and building your own allows you to customize it to suit your specific needs. Here’s a general guide to get you started, but keep in mind that specific details may vary based on the type of CNC machine you want to build (e.g., router, mill, laser cutter). Throughout this procedure I share with you my project in progress for the design of a CNC milling machine, machine that I designated “DC_VMC-A4”.

You can ask for more information on the project or simply contribute to its improvement, in comments or by email ( vmc-a4@digit-chain.com)

Steps to Build a DIY CNC Machine:

Machine Specifications for “DC_VMC-A4” : (link to word file)

1. Frame and Construction:  – Frame material: Aluminum alloy   
– Compact and sturdy design for stability
– fixed table
2. Work Area:  – X-axis travel: 300mm   
– Y-axis travel: 200 mm   
– Z-axis travel: 100 mm
3. Linear Motion System:  – screw nut system for X, Y, and Z axes   
– Linear rail guide for smooth and accurate movement
– Stepper motors for precise control
4. Spindle:  – Spindle type: High-speed brushless DC motor   
– Spindle power: 300W   
– Maximum spindle speed: 8,000 RPM   
– Collet type: ER11
5. Controller and Electronics:  – Controller board: GRBL (or similar)   
– Stepper motor drivers   
– Microcontroller: Arduino uno   
– Power supply: 24V DC
6. Toolhead:  – ER11 collet system for tool compatibility   
– Quick-change tooling capability
7. Accuracy and Precision:  – Positional accuracy: ±0.01mm   
– Repeatability: ±0.02mm
8. Software Compatibility:  – Compatible with popular CNC control software (e.g., Universal G-code Sender)   
– USB interface for easy computer connectivity
9. User Interface:  – Simple LCD or LED display for basic machine status   
– Manual control jog wheels for axis movement
10. Work Surface:  – Work Surface 300 mm x 200 mm
– Sturdy worktable with T-slot for securing materials    
– Effective work area illumination
11. Cooling System:  – Efficient cooling system for the spindle motor    
– Fan or air-assist system to prevent overheating during prolonged use
12. Safety Features:  – Emergency stop button    
– Overcurrent and overheat protection
13. Enclosure:  – Open-frame design for visibility    
– Optional safety enclosure for user protection
14. Operating System Compatibility:– Compatible with Windows, Mac, and Linux operating systems
15. Weight and Portability:  – Lightweight design for easy portability    
– Overall machine weight: 15kg
Machine Spécifications
NOTE: THESE SPECIFICATIONS PROVIDE A BASIC LINE FOR STARTING THE DESIGN OF THE DIY CNC MILLING MACHINE. DEPENDING ON THE CONSTRAINTS: BUDGET, AVAILABILITY OF COMPONENTS, THE DESIGN OF THE MACHINE IS UPGRADED TO MAINTAIN THE FUNCTIONALITIES THAT MEET THE MACHINING NEEDS. WE WILL ALWAYS CONSIDER SAFETY FEATURES AND FOLLOW APPROPRIATE OPERATING GUIDELINES FOR CNC MACHINES.

For the kinematics I opted for a machine with a fixed table. the idea is that it will be simpler, I think, to upgrade the machine to a four-axis or even five-axis machine.

desktop milling machine concept

the dimensions of the table are the travel along the axes (X-axis travel: 300 mm, Y-axis travel: 200mm) plus approximately 20% for accessory mounting. From where L= 1,2 x 300 = 360. l = 1,2 x 200 =240 . We opt for a 350*250 table with 4 T-slots Size 10mm .

CAD FILE T-SLOT TABLE (50 downloads )
Milling macine table drawing

Sizing a linear guide system requires considering several factors. It’s not a one-size-fits-all solution, and choosing the right components involves balancing requirements and budget.
below is a representation of a linear guide for the movement of an axis. The system is composed of the following elements:

  1. guide rail,
  2. screw nut sytem,
  3. screw-nut bearings,
  4. carriage,
  5. frame

We start by defining the minimum lengths of the components (TL) to ensure the travel define in specifications. The travel T = LT + RT.

Representation of a linear guide for the movement of an axis

the selection of the guide rail implies the choice of:

  • Guide rail profile: Square, round, dovetail,  based on load capacity and rigidity needs.
  • Material: Steel offers high strength, aluminum provides weight savings.
  • Bearing type: Ball bearings offer good speed and capacity, roller bearings handle heavier loads, bushings are simpler and low-cost.

For machine tools we generally use Square Guide rail . for the sizing we will assume that EX=EB (EX distance between the two linear bearing) hence the minimum length of the rail is LT = T + (3*EB) EB is the length of the “linear bearing”.
a search on merchant sites (Alibaba, Amazon etc.) we opted for the following solutions:

AxeExample of compliant railLink to CAD file
X-axis travel: 300mm    Coavoo MGN15 Linear Rail 480mm 18.9″ (AMAZON)LINEAR SLIDER 480
Y-axis travel: 200 mm Coavoo MGN15 Linear Rail 330mm 12.99″LINEAR SLIDER 330
Z-axis travel: 100 mmCoavoo MGN15 Linear Rail 230mm 9.06″LINEAR SLIDER 230

To have a price reference, I added “alibaba.com” rail guide offers in my shop.

ball screw assembly
AxeDesignationlink to CAD file
Xassembly of the 300 mm stroke axe system + technical drawing
Yassembly of the 200 mm stroke axe system + technical drawing
Zassembly of the 100 mm stroke axe system + technical drawing

Spindle design is a crucial aspect of mechanical systems for CNC milling machines. The spindle is the rotating axis of the machine, and it plays a significant role in the machine’s performance, accuracy, and durability.
To start with, I adopted a basic design: a shaft supported by two bearings with an SA20 taper. The spindle is driven by a toothed pulley, all mounted in a shouldered cylindrical housing. The milling tool holder is secured by a socket head cap screw.

For the sizing, I based it on the standardized dimensions of the SA20 taper. Once the entire machine is designed, I will resize all the parts to withstand the various mechanical loads generated by machining.

Spindle assembly
Spindle assembly
DesignationDescriptionlink to CAD file
  •   Tree Stepper motor drivers   
  • Microcontroller: Arduino uno   
  • Power supply: 24V DC
  • Relay module 8 channels

the design

The CAD file :

Download “electrical cabinet for DIY Milling Machine”

electrical cabinet.rar – Downloaded 0 times – 1.19 MB

Reminder: this project is currently in progress, I am publishing it to encourage contribution from the web. I will update this post as I go.
For the design software i use the Autodesk suite. I share native Autodesk files, upon request I will send you the requested files in standard exchange format.

CAD FILES DC-VMC-A4_TF 01 (0 downloads )

Leave a Reply