Uses for Rivets in CNC Machining(medical grade plastic Leila)
- source:DAHLER CNC Machining
What is a Rivet?
A rivet is a mechanical fastener that joins two or more materials by passing a metal rod through aligned holes in the materials and forming heads on the protruding ends. The rivet shank expands when the heads are formed, creating a tight fit. The resulting riveted joint is permanent and rigid.
Rivets come in a variety of head shapes, materials, and sizes to suit different applications. Common materials include aluminum, steel, copper, and titanium. The most popular head shapes are round, countersunk, and brazier. Rivet diameters range from 1/16 inch to over 1/2 inch.
Advantages of Rivets in CNC
Rivets offer several advantages that make them a popular choice for CNC machined parts and products:
- Permanent fastening - Once installed, rivets create a permanent, non-reversible joint. This can help improve product durability.
- Vibration resistance - Riveted joints maintain their integrity when subjected to vibration and shock forces. This makes them well-suited for applications like automotive and aircraft assembly.
- Shear strength - The shank expansion characteristic of rivets gives them excellent shear strength. The joint can withstand substantial lateral forces.
- No threads or rework - Rivets do not have threads that can be damaged and do not require rework if assembled incorrectly. This improves production efficiency.
- Material versatility - Rivets are available in a wide range of materials to meet specialized strength, corrosion resistance, or conductivity needs.
- Automation friendly - Installing rivets is highly conducive to automation. CNC machines can be programmed to drill rivet holes and set rivets efficiently.
Common CNC Uses for Rivets
Rivets have many uses in CNC machining processes. Here are some of the most common:
- Sheet metal fabrication - Rivets are ubiquitous in sheet metal products, used to join thin gauges of aluminum, steel, titanium, and other metals. Machinists can program CNC brakes and turret punches to produce riveted sheet metal enclosures and assemblies.
- Aircraft assembly - Thousands of rivets join the aluminum skins to underlying structures in airplanes and helicopters. CNC riveting machines automate this otherwise tedious process for aerospace factories.
- Automotive components - The auto industry relies heavily on rivets to assemble body panels, frames, and interior components. Robotic CNC riveting helps automate mass production.
- Electronics enclosures - Rivets assemble sheet metal electronics enclosures used for computers, instruments, control boxes, and other devices. CNC punching centers pre-punch rivet holes for quick assembly.
- Plumbing fixtures - Hidden rivets join the sheet metal shells of bathtubs, sinks, shower stalls, and other plumbing products made with CNC metalworking equipment.
- Signs - Sheet metal sign faces often use rows of rivets attaching perimeters and decorative elements. CNC routers pre-drill holes for easy riveting.
- Sculptures & decor - For decorative metalworking, artists use rivets as an visible design element or to join artistic creations. CNC mills drill holes for rivet placement.
- Outdoor equipment - Rivets assemble rugged truck toolboxes, off-road vehicle parts, trailers, and agricultural equipment that must withstand harsh conditions.
- Hardware - Hinges, latches, and drawer slides used in furniture and storage products rely on rivets for durable pivoting actions. CNC helps speed high-volume production.
Rivet Materials for CNC
CNC programmed riveting requires selecting the optimal rivet material for each application. Common options include:
- Aluminum - Lightweight yet strong aluminum rivets suit most sheet metal fabrication. Varieties like 5000 series aluminum provide excellent corrosion resistance.
- Steel - For the highest strength and hardness, steel rivets are ideal. Carbon steel, stainless steel, and specialty alloys cover a wide range of uses.
- Copper - With excellent conductivity plus solderability, copper rivets are the choice for electronics applications.
- Monel - This nickel alloy offers the strength of steel with the corrosion resistance of copper. Monel rivets suit demanding marine and chemical exposures.
- Titanium - Extremely strong but lightweight titanium rivets provide high shear strength with low density for aircraft and other uses.
- Brass - Brass rivets have attractive gold coloration for purely decorative purposes where appearance matters.
With many options, CNC programmers can dial in the optimum rivet material based on strength, weight, corrosion, conductivity, and aesthetic needs.
Programming Tips for CNC Riveting
Optimizing CNC machines for rivet installation requires some specialized programming techniques:
- Accurate hole alignment - Rivets require that mating holes align nearly perfectly. Offsets and hole patterns must match on joining parts.
- Hole diameter and tolerance - A rivet hole diameter slightly larger than the rivet shank allows for easy assembly. Tolerances of +/- 0.001” provide a tight final fit.
- Rivet grip range - Specify a grip range slightly less than material stack-up so the rivet fills 70-80% of the hole. This ensures adequate expansion and joint strength.
- Hole chamfers - Chamfering or countersinking hole sides prevents material burrs from obstructing rivet insertion and upset.
- Specialized tooling - Recipe programs should reference specific riveting tools and nosepieces for best results. Tool pressure and impact force should align with rivet size.
- Backup material - Drill exit holes or place soft backup material beneath the riveting surface to absorb impact and prevent part deformation.
- Hole deburring - Adding a deburring step ensures clean, smooth rivet holes for easy insertion and optimal finish.
By considering these factors, CNC programmers can create riveting processes that reliably produce secure, precise joints in automated production.
Rivets are an indispensable fastening solution for CNC projects across countless industries. By leveraging the advantages of rivets along with proper programming techniques, today’s CNC machinery can assemble products quickly, precisely, and efficiently using this simple but mighty mechanical fastener. With continued innovation, the usefulness of the rivet in CNC machining is sure to carry on long into the future. CNC Milling CNC Machining