Producing High Quality Rivets with CNC Machines(typical machining tolerances Rebecca)
- source:MAJA CNC Machining
Like any machining application, starting with quality raw material is key for rivet production in CNC. Most rivets are made from steel, aluminum, copper, or other metal alloys. The material must have consistent chemistry and be free of defects that could lead to rivet failure. CNC machines can process most metal materials into rivets.
CNC Machining Processes for Rivets
The most common CNC process for rivet manufacturing is lathe machining. CNC lathes use rotating cutting tools to shape rivet wire into the required head and shank form. Programmers input the dimensions for head shape, shank diameter, length, and other features. The CNC lathe precisely machines each rivet to match this programmed specification. This ensures every rivet has the proper dimensions to fit in holes and fasten materials together.
Other CNC processes like milling and grinding can produce rivets. CNC milling uses rotating end mills to cut rivet heads and shanks from bar stock feed material. While more waste is produced from milling, it allows more complex rivet shapes than lathe machining. CNC grinding is often used as a secondary process after lathe or milling production. Grinding can add precision and smoothness to rivet shanks and undersides of rivet heads.
In order to machine rivets consistently, CNC machines use fixtures to hold and locate the workpiece. For lathe machining, collets, chucks, and mandrels grip and position rivet wire for turning operations. These high precision fixtures minimize runout and ensure concentricity of the rivet shank. Fixtures for CNC milling may include vises, clamps, jigs, and v-blocks to secure and locate bar stock for rivet milling. Precision fixturing is crucial for proper CNC machining of rivets.
Optimizing Feed Rates and Speeds
For quality results, CNC programmers must determine the right feeds and speeds for rivet machining. Cutting tools rotate and move against the workpiece at these rates during machining. Optimal feed rates and cutting speeds depend on the material, tooling, and desired finish. Generally, harder metals use slower feeds and speeds than softer metals. Improper feeds and speeds can lead to tool wear, chatter, or poor surface finishes in the finished rivet product. CNC allows programmers to dial in the best parameters and adjust as needed.
One key advantage of CNC machining is the ability to integrate inspection processes for quality control. In-machine probes can check critical dimensions like rivet head diameter, shank length, and other attributes. Automated vision inspection can also examine surface defects and measure geometries. Any rivets found out of spec can be flagged or rejected before packing. This CNC inspection automation improves quality while reducing labor costs compared to manual inspection.
In some cases, additional processes beyond CNC machining are needed to finish rivets. Small rivets may require heat treating to increase hardness and strength. Heat treating can also relieve stresses in rivets from prior machining. Plating and coating can apply corrosion protection or colors to rivet surfaces. Printing can mark rivet heads with logos, part numbers, or identification codes. These secondary processes further enhance the quality and functionality of CNC machined rivets.
The last step for quality rivets is proper protective packaging. Typically small plastic bags or bulk boxes are used. Packaging prevents scratches, dirt, and moisture from damaging rivets before installation. It also keeps different rivet sizes and lengths organized and identifiable for the end user. Good packaging is cheap rivet insurance.
In summary, CNC machining paired with quality raw materials, fixtures, parameters, and secondary processes allows efficient production of high precision rivets. This combination maximizes quality control of rivet dimensions and features. By optimizing every production step, CNC technology reliably delivers exceptional rivets for all types of assembly applications. CNC automation not only improves rivet quality, but also reduces production costs compared to manual fabrication methods. The precision and consistency of CNC machines will continue to drive innovations in rivet design and performance. CNC Milling CNC Machining