During milling or other machining work, a workpiece needs to be clamped quickly and precisely. Commonly used manual clamping is a relatively cheap and easy solution with significant holding power. On the other hand, magnetic clamping can be quicker, prevents unwanted vibrations, and there’s no risk of deforming the workpiece. How to decide between the two?
Manual Clamping: Pros and Cons
Many production operations still use traditional manual clamps with workers installing the workpiece in the clamp by hand. Manual clamps are ubiquitous tools that can be found in everyone’s garage; these represent an effective clamping method that is easy, inexpensive and accessible to everyone.
Nevertheless, manual clamping has its cons. The workpiece to be machined is never clamped with the same force all around its perimeter, and that can cause unwanted vibrations (occurring further from the clamp’s jaws—especially when machining asymmetrical workpieces). Manually clamped workpieces may move or even come loose—that means having to clamp the workpiece repeatedly if you are lucky. If not, the workpiece may be irretrievably damaged. Finally, manual clamping is quite time-consuming.
Manual clamping carries a risk of deforming the workpiece if clamped too tightly. Due to the jaws of the clamp, the workpiece is never freely accessible from all sides, which may result in having to re-clamp it during machining. That takes time—and time is money. Manual clamps also require regular servicing and maintenance (tightening and oiling).
Magnetic Clamping: Pros and Cons
Clamping a workpiece with a magnetic chuck eliminates most cons of manual clamping. The workpiece is attached to the workstation using the same clamping force all around. There are absolutely no vibrations and there’s no risk of the workpiece moving or coming loose on condition proper clamping procedure is maintained.
A magnetically clamped workpiece cannot be deformed and is easily accessible from all sides. Using a magnetic chuck is much quicker than clamping a workpiece manually, once the operator has been trained. A magnetic chuck does not need to be maintained—there are no movable parts or screws that would require regular care.
Manufacturing capacity increase
Once your operator is trained, it’s much quicker to clamp a workpiece with a magnetic chuck than with a manual clamp. Let’s say an operator averagely spends eight minutes clamping a workpiece manually—with a magnetic chuck, clamping can take just a minute. That can increase your manufacturing capacity by 25 %.
One of the cons of magnetic chucks is their higher initial cost (compared to manual clamps). However, the initial investment pays off very soon due to manufacturing capacity increase.
Take this example: The price of our Mastermill magnetic chuck is approx. 5.600 EUR. This investment will be returned in just one month (in a double-shift production) or two months (in one-shift productions).
Cons of magnetic clamping
We’ve already mentioned their higher initial investment. Moreover, there are staff training requirements to work with magnetic chucks. And then there’s the obvious disadvantage: magnetic chucks cannot be used to clamp non-magnetic material (e.g., aluminium).
Which type of clamping? The payoff
Each production is different, so it’s up to you to calculate the return on investment in your specific case (how many magnets are you getting, their type, size, etc.). Every manufacturer needs to do their math first and calculate the most financially savvy solution for them.
From our experience, magnetic chucks bring the most benefits to factories that machine more complicated workpieces—clamping such workpieces manually would mean wasting precious time. Manual clamping, on the other hand, is necessary when working with non-magnetic materials like aluminium.
In case you still use manual clamps in your factory and are interested in trying out magnetic chucks, do let us know! We will gladly advise you while you make your choice. We even offer free trials of magnetic chucks for a few days so that you can test their pros and cons in practice.