CNC machining thin sheet material has traditionally been plagued with challenges—many of which are time-consuming, frustrating, and difficult to overcome, especially when working with thin materials. In this blog, we’ll explore various methods of securing sheet material for CNC machining, highlighting their advantages and disadvantages. We’ll also introduce a revolutionary solution developed by DATRON that transforms the process altogether.
The Challenge of Thin, Non-Structural Materials
Thin sheets are inherently less rigid, making edge clamping nearly impossible. Securing the perimeter with mechanical clamps often results in the sheet lifting or shifting during machining. The end mill’s cutting forces tend to pull the material upward, causing movement and inaccuracies. Operators often run machines at slower speeds to mitigate this, sacrificing productivity. Additionally, custom clamping solutions—such as toe clamps—require time to set up and remove, adding to costs and cycle times.
Using Inner Fastening Areas
If your design allows, you can machine a matrix of parts or incorporate accessible areas for fastening. You can secure the sheet without damaging your parts by designing custom sub-plates or using standard fixture plates with a grid of threaded holes. However, this approach involves predrilling, threading, and removing fasteners after machining, increasing setup time and cost.
Adhesives as a Securing Method
Double-sided tape is a popular alternative, preventing the sheet from lifting, especially in the center. Yet, applying and removing tape adds extra steps, and coolant can degrade the adhesive over time. For cutting through sheets, adhesive buildup on tools and chips can cause cleanup issues. Additionally, removing tape without deforming the workpiece can be tricky for small, thin parts.
Standard Vacuum Tables and Chucks
Vacuum tables—usually aluminum chucks with a grid of grooves—are widely used. They hold sheets quickly and firmly when fitted with a neoprene gasket and connected to a vacuum pump. However, a significant drawback is that you cannot cut through within the gasket area; doing so would lose the vacuum, requiring secondary operations or alternative fixturing.
DATRON’s Innovative Vacuum System
Enter DATRON’s groundbreaking solution—an advanced vacuum table that handles profiling, cut-through holes, and small parts as tiny as a nickel. This system is ideal for nonferrous materials like aluminum and composites because ethanol is the coolant. It will not work with flood coolant systems.
How It Works:
The table features an aluminum chuck with a grid of meandering grooves fed by micro-holes that evenly distribute vacuum. A permeable, sacrificial layer of cardboard or similar material is placed over the chuck, with your sheet on top. The vacuum pulls through the permeable material, securely holding the sheet regardless of whether the cut penetrates completely through. This allows for fast part removal without screws, tape, or gaskets.
Benefits:
- No setup time for fixtures
- No residue or damage from adhesives
- Easily replaceable sacrificial layer for rapid throughput
- Modular sizes for large or small production runs
- Compatible with high RPM systems, ensuring minimal movement of small parts during machining
Pro Tip:
DATRON offers specialized permeable stock with a low-tack adhesive, similar to Post-it® notes. It provides extra grip for small parts without leaving a residue on tools or parts.
Conclusion
Whether you’re machining small or large parts from aluminum or plastics, DATRON’s vacuum table systems offer an efficient, clean, and precise solution for CNC machining thin sheet materials. Contact a DATRON representative to explore how this innovative technology can streamline your production process and reduce setup times.
See How a DATRON Customer Batch Mills Small Parts from Thin Sheet Aluminum
