An automated pallet change (APC) system is something you may want to consider for your manufacturing shop. But how do you know if it is right for you?
Before we jump into the dos and don'ts of APCs, let's talk about where they started. Add-on CNC pallet changers have been around for a few years. They increase spindle uptime by moving the loading and unloading to the outside of the machine, which keeps the spindle running and making money. Almost all machine tool manufacturers now offer add-on pallet changers or work with aftermarket suppliers to offer this option to their customers.
This kind of pallet changer is great if you have high-volume runs or limited part numbers in your shop. Many OEMs took hold of this kind of pallet changer overnight as the ROI was easy to justify. It took longer for contract shops, as they had too many part numbers and variances from customers. However, machine utilization and cost pressure on parts had many contract shops buying add-on pallet changers.
To be able to run multiple part configurations within one machine and increase the acceptance of add-on pallet changers, tool magazine capacities had to be increased. The machine tool industry quickly expanded magazine capacities and offered outside-the-machine chain systems that could increase tooling capacities to hundreds if desired. OEMs adopted this capacity increase quickly. It took longer for contract shops, as the cost of tooling and space for the larger tool magazines needed to be justified.
The next step was adding machine touch probing and part locating systems. Now, the machine computing power was the bottleneck. Machine tool software developers increased memory, processing speed, and capability, and CAD/CAM systems were upgraded to handle the extra computing requirements needed. This gave shops the ability to efficiently handle multiple part configurations and tools, further reducing idle spindles.
The next challenge was the human factor. We used to have one operator managing one machine. The add-on pallet changer allowed us to have one operator managing more machines, further reducing shop costs. Now, captive shops started to add pallet changers, realizing the human resources and machine utilization benefits.
A step up from a pallet changer attached to your machine is a fully automated pallet change system. This system is usually connected to multiple CNC machines via rails, AGV (automated guided vehicle), robotics, or other means of transporting pallets to the machine. The center of these systems is a computer that communicates with all CNC machines, transport systems, your CAD/CAM software, and your tooling. This results in the ability to know which machines can handle which jobs. For example, you could machine the basic operation on a standard 3-axis CNC and then move the pallet to a 5-axis machine for only that portion of the work, freeing your high-dollar, multi-axis machine for more lucrative work.
The system is also tied to your MES, ERP, or other shop floor management systems, allowing them to prioritize workload and delivery while utilizing all equipment for the best possible OEE and ROI. More and more companies are also looking at APC systems as they have difficulty finding staff.
To see if your shop is a candidate for an APC system, you need to ask yourself a few questions.
Do I have enough work to utilize the machines 24/7?
Do I have the technical resources:
Tooling quantities and capabilities
Fixture design and build capabilities
Can this system help me grow my business?
Attract more work
Reduce part and/or operating costs
Solve manpower shortage
Improve on-time delivery
Are you willing to make the capital investment?
If you answered yes to most or all of these questions, you should consider an APC system.
Where do you start?
If you don’t have a qualified in-house engineering staff member, talk to your machine distributors and ask if they have an in-house automation or integration solution group. You can also contact an external integrator and have them work with you and your supplier to design a system that meets your needs.
Questions to ask include:
What do you do, and how do you do it?
Do you work with only one brand of machines?
Do you design, install, and maintain the system?
Which parts of the system are you responsible for?
Where do you get replacement parts?
Can you design a modular system?
Can the system handle vertical and horizontal machines?
Is this system expandable?
Can you interface with other systems in the future?
Do you offer support for:
Tooling or fixtures?
Interfacing with your ERP, MES, MRP, etc.?
Do you provide help with cost justification, such as:
What kind of operating cost can you expect from the system?
There is a lot of homework you need to do before buying an APC system for your shop. In my experience, an APC system that is well designed and thought out will pay for itself in a reasonable amount of time. However, there are some pitfalls you need to be aware of:
Are you able to run the system 24 hours a day?
Do you have in-house technical expertise to ensure the system is maintained?
Will your sales force bring enough work to keep the APC busy?
Can your organization handle an increased workload?
I hope you will invest some time and resources to see if an APC system might be a game changer for your shop.