Deburring Robots: More Accessible Than Ever
Manufacturers often need to smooth down the rough edges that result from welding, casting, injection molding, drilling, turning, and milling. All these fabricating operations require deburring.
Today, finding employees to perform this work represents a massive challenge. In the U.S. there were more than 800,000 unfilled manufacturing jobs in July 2022 according to the National Association of Manufacturers, with a forecasted 2.1 million unfilled positions by 2030.
Manufacturers report hiring more people for a job than they actually need because of high turnover. Firms are continually searching for whatever method possible to increase productivity.
Older workers are retiring, and younger workers tend to have less tolerance for the strenuous and tiring work of deburring. Repetitive motion injuries are common, especially carpal tunnel syndrome and back strains. Dust and particulate matter fly off the workpiece, and when inhaled can create serious health hazards. Workers must wear eye protection, dust masks, gloves, and other skin protection. Harmful chemicals can also be released when working with composite materials during a deburring operation. Ventilation systems can pull dust and fumes from the air, though such equipment is expensive and requires frequent filter changes and maintenance.
It’s no surprise then, that dedicated deburring departments have difficulties retaining employees in such a dirty, dull, and dangerous environment. Combine these factors, and you have a strong case for robotic deburring.
Properly equipped robots are not affected by dust particles or chemical vapors and can deliver more consistent results. Yet, most manufacturers have not adopted robotic deburring. Until recently, the tasks were considered too variable and complex for a robot. In the past, unless the part volume was high and the variety of parts was small, the cost of a robotic deburring solution was considered prohibitive. Articulated robot arms were expensive, programming the robot took too long, and the coding expertise required high-priced and scarce talent.
Thankfully, this is no longer the case. Recent developments in computer vision and advancements in robotic programming have changed the picture. More deburring tasks can now be automated cost-effectively than ever before.
Industries Utilizing Deburring Robots
Automotive manufacturers were the first large-scale adopters of robotic automation. Because their part volume is high, auto-makers could justify the expense of robotic deburring. Engine blocks have many edges that need to be deburred. Metal castings of engine components, brake assemblies, and transmission parts have rough edges that must be ground down and smoothed out.
The volume of aerospace manufacturing is much lower than automotive, and sometimes low-volume operations make it difficult to cost justify an investment into robotics and automation. However, tolerances in the aerospace industry are extraordinarily tight. The necessity for extremely high quality and consistency has driven the adoption of robotic deburring.
The fuselages of planes, helicopters, and other aerospace vehicles feature lots of sheet metal. Cut sheet metal pieces and stamped parts have ragged edges that need to be deburred. Specialized equipment for sheet metal edge deburring features abrasives that revolve while they rotate for even results on all edges.
Aerospace engine parts must comply with stringent specifications and are a prime example of the application of robotic deburring.
Different kinds of robots can be used and combined when the parts are large. An overhead gantry with a robot arm attached can travel the entire length of a large aircraft, deburring as it goes.
Low Volume, High Mix Manufacturing
Even industries characterized by low unit volume and a high mixture of different products can benefit from robotic deburring cost-effectively. The reason is modern robots are more flexible and multi-purpose than ever before.
A work cell with a robot arm in the center shows how a multi-purpose robot can function. Many parts require a series of deburring steps to be performed before they become usable. Specialized equipment can often carry out one task, but the workpieces must be fed into a series of machines in sequence. This is an excellent application for an articulated robot arm. In this case, the robot does not perform the deburring operation itself, and instead tends to the deburring machines.
By locating the robot in the center of a group of deburring machines, the arm can tend to each piece of equipment. The robot inserts and removes the parts as needed, sequencing them through the appropriate set of procedures. If parts become hot as the result of a deburring process, the robot can immerse the part into a cooling medium before inserting it into the next machine.
An alternative geometry puts the robot arm onto a linear track. Specialized deburring machines can be arranged in a row, and the robot travels from one piece of equipment to the next on a kind of rail system.
The same robot arm can place each finished piece into a fixture where a computer vision system inspects it for quality control. With a tool change, the robot can be equipped with calipers or other instruments which allow the robot to perform the measurements directly.
As a last step, the robot can place the finished workpieces onto a conveyor or into a tray.
The Flexibility of Automatic Tool Changing
One of the reasons modern robot arms are so flexible is that they can automatically change tools. One tool might enable the robot to debur the inside of a rounded part. Another End-of-Arm-Tool (EoAT) allows the robot to debur the edges of a flat piece. The robot can change its function by automatically installing a gripper, permitting it to perform pick-and-place operations.
This flexibility may be a crucial part of justifying the investment into robotics. For a small manufacturer, if the robot is only used for deburring, the benefit might not justify the expense. But a multi-purpose robot may change the equation.
Improvements in Programming
In recent years, innovations in the field of robot programming have made automating industrial processes easier and faster. An example is the open-source technology called “Scan-N-Plan.”
This technology is designed to use image processing to plan the path a tool must take to perform an industrial operation such as deburring. The concept is to replace the older, offline programming that uses a simulated version of the workpiece and robot. Typically, such programming is done with a computer-aided-design (CAD) model of the workpiece. One difficulty with this older type of programming is that CAD models are not always available, and expert programming is typically required.
Scan-n-Plan is also a replacement for online programming involving a teach pendant, in which an operator “teaches” the robot by moving it into a series of poses. Although a teach pendant does not require an expert programmer, depending on the part and the operations to be performed, it can be tedious and time-consuming.
Scan-n-Plan allows a user to take a 3D image of the workpiece, and from that data derive the path the robot arm is to take. The technology can be generalized to apply to many different kinds of applications, such as painting, polishing, and more.
Some vendors have taken this concept and developed proprietary solutions for specific applications. The user who wants to automate their deburring process can take advantage of these developments.
The benefit is that programming a robot to perform an industrial operation is simpler and quicker than ever before.
Benefits and Challenges
Robotic deburring has many benefits. However, it doesn’t make sense in all cases, and some challenges must be addressed.
- Higher quality and consistency – manual deburring is inherently inconsistent. Modern robots have force sensing that enables them to apply the same amount of force if working on the top of a surface, coming from underneath, or from any angle. Robots excel at performing precisely the same task indefinitely, something humans find difficult to do.
- Higher productivity and shorter cycle times – robotic deburring is faster than manual methods. The robot arm can be stronger than a human one, so a robot can remove material at a more aggressive rate. The robot can orient itself into positions that would be uncomfortable or impossible for a human and thereby reduce processing time.
- Fewer rejects – the higher quality from a robotic process means fewer defective parts, which translates to cost savings.
- Safety – automation keeps associates healthy by relieving them of a task with a high risk of repetitive motion injuries and lung problems. The vibration of a deburring tool can cause people to develop nerve problems.
- Don’t try to automate everything – to achieve a cost-effective robotic deburring operation, keep in mind the principle that you spend 20% of the investment to handle 80% of the parts. Trying to automate 100% of parts could end up defeating your purpose.
- Expertise – consulting an abrasives expert or partnering with a vendor with deep experience in deburring automation is probably necessary. The deburring process has a lot of variables that affect the end result: the robot speed, the force applied, the type of bit or abrasives used, the rate the abrasive media wears out, the angle of the tooling, and the positioning of the part.
- Floor layout – many times, the floor plan will need to be changed to accommodate the robotic process.
- Fixturing and gripping – how the workpieces will be gripped and held is an important consideration. Automating a manual process may require special fixtures or grippers.
The shortage of qualified workers is a critical factor driving robotic deburring adoption. Robots can get the work done, often faster and with better results when compared to manual methods. Recent technological advancements make automation accessible even to smaller manufacturers with low volumes and a high mix of products.