Turning Machines Automation Systems
Gantry loader vs Bar feeder vs Robot
Shops and automation are two concepts that go hand and hand with the increasing demand for productivity. Automation is not a new topic either. It is a recent year's advancement, but it is becoming much easier and user-friendly to use. Along with being effective and affordable, automation also creates a great opportunity to get the advantage of this technology.
CNC business requires high qualification from the workers and the cost of labor is something that should be observed at the same time. Therefore automation comes into place and ultimately its full implementation often becomes the goal.
Lathe machine shops have a number of automation systems that can be adapted to the machine in search of increased productivity. Because of the often times standardized and easy to work with blank shapes and not only most shops that utilize CNC turning in their manufacturing takes advantage of either a bar feeder, robot or a gantry loader in the search to keep the machine running time increased. A great asset is that it is helping not only the shop owner but also makes the job of the workers lighter and more effective. This makes it a win-win situation as the employees are kept at their positions without sacrificing human labor for automation as the investment quickly pays off. It is a fact that depending on the manufacturing specifics after a machine shop receives automatization a single worker will be able to maintain running a few machines simultaneously.
Is automation difficult to set and run?
The answer is simply no. However, it proposes a different approach and in order to get full advantage of the automation processes, modern machines offer a variety of optional accessories and features to make automated processes predictable and secure. Depending on which one of the three types is selected and implemented many additional functions of the machine could be mandatory or very useful to have included. To name some of them this could be an automatic door opening function for the robots or top opening for the gantry loaders, parts catcher for the bar feeder machines, interface preparation for the external device, automatic tool preseter arm for tool breakage control and measurement, load monitoring system to prevent the machine running if a broken tool is detected, workpiece flyout detection system.
All three systems in this article will have prevailing advantages and utilization depending on the type of work, part, and machine size, automation system machine footprint size, material management, versatility, cycle times, lathe machine options to be included ... the list can go on even further. With the nowadays digital capabilities automation can reach even higher levels with the machines providing essential information used within Industry 4.0 and the internet of things allowing for receiving messages for work interruptions and receiving statistical data and reports.
Bar feeder is probably the most widely spread system because it is the cheapest solution with prices varying from about $5000 for the simple and small systems to $20-30000 for the expensive ones. The bar length usually varies from 4-5 feet for the shortest up to 19 feet. There are hydraulic operated bar feeder systems for manual bar change and automated ones the latter of which come in different types some of them having automated pallet stations themselves.
They are the best solution for Swiss-type machines and small and mid-sized conventional type lathes, twin-turret, and two-spindle lathes mainly because they can offer the quickest chip-to-chip times from only about 2 seconds. Thus bar feeders are the best high-volume solution for large batch sizes.
A drawback of the barfed automated lathes is that if the machine only has 1 spindle the part cannot be machined from both sides. Therefore for this case depending on the working part configuration, the bar feeder can appear to be either the best or not so optimal choice solution in terms of full automation. However, it depends on how the workshop is organized as well.
Bar feeders are also ready to use only by starting them and programming by creating a simple macro allows for a really quick set for a new part.
Gantry loaders unlike the bar feeder systems are probably less spread systems. They have a larger footprint, higher price range starting from about $20000 but of course, they come with their advantages as well.
The gantry loader is a bit more flexible system than the bar feeder with the difference that the part blanks should be cut and stacked on a pallet. The first thing to mention is that gantry loaders are suitable not only for single-spindle lathes but for automated lathe systems like the front-facing spindle lathe stations which act like a complete lathe cell. A highly useful option of a gantry loader could be the servo-driven B-axis on the gripper that can rotate and allow for the part to either be flipped and the other side to be machined or both spindles of a two-spindle lathe to be machined or the part to be transferred to another gantry arm in the case of the front-facing type lathe cells.
Gantry loaders usually come with a remote control and are easy to manipulate as well. They also have limitations in terms of size with the most common solutions being appropriate for parts sized up to 6-8in and weight up to 10-20lb. Talking about timing some models can have times of about 6 seconds to load a new part.
Robots are the most versatile automation solutions. Just by placing them in the range of the arm, they can assist in making any workstation automated. It has been a recent tendency that some CNC lathe manufacturers are even offering a built-in robot as an already complete automation solution.
Actually, robot arm solutions can be either a more sophisticated and strong industrial robot solution or the lightweight and easy-to-use cobots which are more affordable than the $50000 starting price of most industrial robots. Robots are also much more precise, can lift a heavy load which makes them the best solution for large-sized pieces, have larger ranges, and are suitable for higher volume and high-speed production.
Cobots are basically designed to work alongside the worker and they are safe if you enter the area of operation because they will put on hold their process and industrial robots on the other side need to have a fenced cell for security reasons. So basically the cobots are the desktop robot version for a lower volume and more versatile part machine shops as they are very easy to change their workstation or tasks.
A great advantage to be mentioned about the industrial robots is the possibility to form an industrial cell with them and other CNC machines, being it a lathe, milling machine, grinder, etc. So although not on the topic of lathe automation it is important to be said that unlike bar feeder systems and gantry loaders, which are mostly implemented for lathe automation, robots on the other side are extremely versatile and can be switched to any working cell that "needs a hand". They can also be used in combination with bar feeders in a cell-type organization in order to make the automatization process even more complete and technology advanced.