Choosing the correct Plywood thickness is one of the most important decisions in CNC Routing and furniture fabrication workflows. Thickness directly affects structural strength, joinery performance, machining behavior, weight, and assembly stability.
Different furniture applications often require different material thicknesses.
Common Plywood Thicknesses
The most common plywood thicknesses used in CNC furniture are:
- 6 mm
- 9 mm
- 12 mm
- 15 mm
- 18 mm
- 24 mm
Each thickness behaves differently during fabrication and structural use.
12 mm Plywood
12 mm plywood is commonly used for:
- lightweight furniture
- decorative panels
- storage systems
- small shelving
- laser-cut assemblies
Advantages:
- lighter weight
- easier machining
- lower material cost
Limitations:
- reduced rigidity
- lower load capacity
- more flex in large spans
15 mm Plywood
15 mm plywood is often used as a balance between strength and weight.
Common applications include:
- modular furniture
- cabinets
- medium-load shelving
- flat-pack systems
It provides better rigidity than 12 mm material while remaining relatively lightweight.
18 mm Plywood
18 mm plywood is one of the most popular choices for CNC furniture.
Applications include:
- tables
- shelving systems
- cabinets
- workshop furniture
- structural assemblies
Advantages include:
- strong structural performance
- reliable joinery
- good screw holding strength
- stable friction-fit assemblies
Many CNC furniture systems are designed around 18 mm sheet materials.
24 mm Plywood
24 mm plywood is commonly used for heavy-duty applications.
Typical uses include:
- large tables
- workbenches
- structural furniture
- high-load shelving
However, thicker material increases:
- weight
- machining time
- material cost
Thickness and Joinery
Material thickness strongly affects Joinery Design.
Important considerations include:
- slot sizing
- tab dimensions
- friction-fit tolerance
- fastener depth
- structural rigidity
Incorrect thickness assumptions may cause assembly problems.
Nominal vs Actual Thickness
Plywood thickness often differs slightly from its labeled size.
For example:
| Nominal thickness | Actual thickness |
|---|---|
| 18 mm | 17.2–18.5 mm |
| 12 mm | 11.4–12.2 mm |
Thickness variation is especially important for press-fit and slot-fit systems.
Thickness and CNC Machining
Thicker materials require different machining strategies.
Important factors include:
- tool length
- cutting depth
- feed rates
- spindle load
- machining time
Deep cuts may increase vibration and tool deflection.
Weight Considerations
Thicker plywood significantly increases furniture weight.
This affects:
- portability
- shipping cost
- assembly handling
- flat-pack efficiency
Weight becomes especially important in modular systems.
Which Thickness Is Best?
There is no universal “best” plywood thickness.
| Application | Common thickness |
|---|---|
| Decorative panels | 6–12 mm |
| Lightweight furniture | 12 mm |
| General CNC furniture | 15–18 mm |
| Heavy-duty furniture | 24 mm |
18 mm plywood is often considered the most versatile option for CNC furniture workflows.