CNC (Computer Numerically Controlled) Machines are used extensively in manufacture of mechanical components and parts. They use computer logic to execute a pre-programmed sequence of machine control commands to operate and machine the required part. Modern machines often combine multiple tools into a single “cell”. Nearly 80% of the auto component suppliers in India use CNC machines to produce the parts for automobiles.
Loading and unloading of parts in the CNC machine, however, has largely remained manual. The process involves an operator loading parts into the machine then unloading them once machining is complete.This is a repetitive and low skill job which often results in the operator feeling underutilized and taking the first opportunity to leave the organization for a more meaningful job elsewhere. Labor related issues spring up such as labor turnover, low productivity, and labor retainership are common bottlenecks observed in production.For the organization this means loss of production since they now have to recruit and train another operator who will take time to come up to speed on productivity.
CNC Machine tending therefore, is ripe for automation. Companies are looking at introducing robots into their shopfloors. This observation is corroborated by a recent market research we undertook, which involved meeting various CXOs in a sample market in Bangalore. Nearly everyone we met seemed to have arrived at a stage where there is a huge need to automate a particular tedious task. Let us explore what it takes to automate this process with an industrial robot.
The most popular flexible automated applications of machine tending would be where robots would load raw material, the machine then executes its program, the robot takes the finished part out and loads the machine with another raw part. This process can be done in a loop for an infinite number of times assuming the robot continually receives raw parts and that the machine produces quality parts.
There are several factors that come into play when involving a robot to this application, here are a few:
- Repeatability: – The robot’s ability to return to a specific XYZ coordinate in space at certain distance, time and time again. In this case, if you are trying to hit a bull’s-eye with a dart, you’re repeatability is how often you hit the bull’s-eye compared to the total number of tries you make. The more times you hit it, the higher your repeatability.
- Speed: – This is how fast a robot can move from point A to point B.
- Cycle time: – This is how fast a robot completes a single task. This is usually picking a part, placing it, and returning to the first point.
- Payload: – The amount of weight a robot can handle doing it’s operation in full capacity.
- Reach: – This is how far a robot can reach in a horizontal direction. Usually, this is a radius measured from the center of the base of the robot.
Apart from the obvious factors mentioned above there are a few external factors involved such as grippers, fixtures and other tools and the type of machine deployed.
When designing a solution for this application, it is very important to have all of these aspects well-defined. The robot will be programmed to go to a specific location taking into account cycle time requirements, payload, reach, repeatability, and accuracy. If they aren’t accurate, then one or more of the robot properties will be adversely affected because the robot will be specified in order to maximize the number of parts produced.
At Systemantics, our flagship ASYSTR 600 robot is primarily built to address the CNC machine tending market. With a payload of upto 5KG and reach of 900mm, this robot has the capability to tend to two machines which improves overall productivity and ROI.
Here is a link to our whitepaper that has a sample use case study with ROI: