CNC machining and sheet metal fabrication are two distinct metal manufacturing processes. However, you can combine both techniques to produce unique and remarkable results. You don’t always have to begin CNC machining with a solid metal block. A sheet metal fabricated part can also act as the starting point in the creation of accurate and aesthetically appealing parts across manufacturing industries.
Though the combination of sheet metal fabrication and CNC machining is revolutionizing the manufacturing sector, you have to understand how both processes work. This article will explain how you can CNC machine sheet metals, the types of CNC machines you can use for secondary operations, and considerations to get the best results.
Can You CNC Machine Fabricated Sheet Metal
The answer to this question is a resounding YES. It is possible to CNC machine a sheet metal after you’ve cut, punched, or formed it using various techniques. There are various ways you can utilize CNC machining to refine and add more features to already fabricated parts.
- Enhance Edges and Corners
You can use CNC machining to refine the corners and edges of fabricated parts. Sheet metal fabrication often results in sharp and rough edges that are not aesthetically appealing and safe for handling. By deburring and creating precise angled edges with CNC machining, the parts function better and it becomes easier to assemble them to make a whole.
- Add Pockets and Holes
CNC machining has simplified the process of adding pockets and holes to fabricated sheet metals. These features are important as they serve several purposes. Precision CNC drilling of straight holes creates pathways for fasteners, cables, and drainage channels. Furthermore, you can use pockets and holes as designs and to enhance heat flow.
- Machining Parts With Tight Tolerances
The tolerance level of fabricated sheet metals is often loose and is usually +/- 0.1mm. Hence, you may have to further process them using CNC machining to make them suitable for use in certain applications. CNC machining accurately controls a wide range of tools and machinery. This process is repeatable and you can make adjustments in real time.
- Improve Surface Finish
Sheet metal fabrication usually produces parts with a rough surface finish. A smooth finish is important in some applications to decrease friction and reduce the risk of corrosion. You can use CNC machines to polish and grind fabricated parts for a glossy finish. CNC machining is automated and suitable for secondary processing.
- Machining Small and Intricate Details
You can carry out CNC machining to machine small and intricate details that would have been difficult with sheet metal fabrication. The CAD software optimizes tool paths which makes it easy to cut thin slots and drill small holes. The use of 5-axis CNC machining after sheet metal fabrication makes all the difference. With this operation, you can reach all sides and tight spaces to create small details and designs.
Types of CNC Machines for Secondary Processing
There are various types of CNC machines you can employ for secondary processing. The following are the most common
- Milling Machines
Mills are one of the most popular CNC machines you can use to further process fabricated metal sheets. It is easy to perform various milling operations such as face milling, plain milling, form milling, and angular milling. All these help to create curves and contours in aircraft parts, car body panels, and electronic enclosures.
- Drilling Machines
Many fabricated sheet metal parts require accurately drilled holes to function. These machines can either create holes from scratch or resize existing ones. These holes are useful for architectural metal works, building construction, and manufacturing of consumer goods. You can also use them for automotive interiors and shipbuilding.
- Grinders
CNC grinding uses rotating wheels to remove excess material from the surface of a fabricated workpiece. Surface grinding allows you to create a flat surface, intricate shapes, and a smoother finish. You can also use CNC grinders to grind internal features and correct irregularities in a fabricated part.
- Laser Cutting Machines
CNC lasers are another machine suitable for already fabricated metal sheets. You can employ laser-cutting machines to produce accurate cuts, shapes, and profiles. Furthermore, these machines are ideal for marking and engraving tiny texts and features on decorative parts.
- Plasma Cutting Machines
Plasma cutters are popular for accurately cutting through fabricated metal sheets of 6 inches or less. You can use these machines to create custom designs and to prepare the fabricated parts for welding operations. Plasma cutters are also appropriate for cutting artistic patterns for various projects.
Considerations and Tips for CNC Machining Fabricated Sheet Metal
Though the process of CNC machining fabricated sheet metals is pretty straightforward, there are some factors you should keep in mind to get the best results. The following are some CNC machining fabricated metal sheet considerations.
- Material Selection
Material compatibility is important when CNC machining fabricated sheet metal. It is not every material suitable for sheet fabrication you can use for CNC machining. Go for a metal that is versatile and meets both techniques’ requirements. For example, aluminum, brass, and titanium are ductile and easy to machine. They do not require much effort when you are working on them.
- Thickness and Size
The size and thickness level of the fabricated part will determine the success of the CNC machining operation. The part’s size must match the machine’s capabilities and the total area it can cover when moving across various axes. Furthermore, consider the thickness of the part. Too thin or thick sheets are prone to warpage and distortion.
- Tooling and Fixturing
The cutting tools and work-holding fixtures are also key considerations. Ensure that the tooling material matches the properties of the material of the fabricated parts. Use tools made of high-speed steel or carbide for a smooth operation. Furthermore, use appropriate fixtures to secure the workpiece during machining. Proper positioning and alignment are important to obtain accurate results.
- Coolant and Lubrication
When CNC machining fabricated sheet metals, it is important to use coolants and lubricants. CNC coolants prevent overheating and facilitate efficient chip removal. They also minimize discoloration and extend the life of the cutting tool. Note that lubricants are different from coolants though they perform interrelated functions. Lubricants reduce friction and protect the surface of the fabricated part.
- Operator Expertise
You must be skilled in both CNC machining and sheet metal fabrication to maximize the capabilities of both operations. A high skill level is important for quick identification and resolution of issues. Experience and expertise will reduce downtime, enhance creativity, and give you a competitive edge.
Conclusion
Combining the versatility of sheet metal fabrication and the speed of CNC machining will give parts with unmatched quality. As a novice or experienced manufacturer, there are some manufacturing tips you should know to maximize the benefits of both techniques. When employing CNC after sheet metal fabrication, ensure that you use a compatible material and part’s size matches the machine’s work envelope. You must also be skilled and experienced in both techniques to make the most use of them.
