Fast-mounted safety clamping precision machining

When it comes to the magnetic clamping technology of the workpiece, the installation time, auxiliary time, and diversity of the application of the fixture are all very important, and the time must be shortened as much as possible. Therefore, Hamburg's EMA machine tool and equipment manufacturing company uses magnetic clamping technology to clamp ferromagnetic large workpieces.

In the processing of large workpieces, magnetic chucks and other magnetic clamping clips have many advantages; in the Precision Machining of large and heavy workpieces, magnetic clamping technology plays an important role. Hamburg's EMA company specializes in high-precision machining of large-sized workpieces. They use the magnetic fixture Magnos developed by Schunk Co., a professional manufacturer of grippers and robots in Lauffen, to clamp workpieces to complete the precision machining of large and heavy workpieces. . There are many reasons for using magnetic clamps. For example, compared with other clamping methods, the magnetic fixture has a short mounting time, workpiece clamping and clamping are safe and reliable, and the precision machining performance of large and heavy workpieces is good.

Since 1978, EMA has entered the field of machine tools and equipment manufacturing. They can produce large heavy-duty workpieces with a length of 3000mm and a weight of 8t to complete the precision machining of such large and heavy workpieces. In addition, they are also responsible for completing the assembly of such machine components and for the commissioning of large and heavy workpieces. For these large and heavy workpieces, quality is first. At present, the company has 12 CNC machine tools, one of which is a five-axis machining center, eight horizontal machine tools and one vertical machine tool. In addition, there are two turning machines, a vertical lathe and a horizontal lathe.

Whether it is aluminum or hard-to-process chromium-nickel alloys, they can be processed in a variety of materials. What the market needs is a fast, innovative solution, and the most important is a very flexible solution. Therefore, EMA will regularly invest in modern machine tools and processing technology. Not long ago, the HEC 1600 machining center, which they purchased from Starrag-Heckert, had just been commissioned and put into production. It was able to complete the precision machining of ultra-large workpieces with a weight of 8 tons and a maximum swing diameter of 3000 mm.

Figure 1 Total of 200 electromagnets in four parallel magnetic chucks

Figure 2 After the current is switched on, the permanent magnet sucker can safely hold the workpiece. Even if the power is cut off, it will not affect the clamping effect at all.

For safe, vibration-free clamping of workpieces, the factory in Hamburg used Magnos magnetic clamps. This magnetic fixture has a total of four MFR 1-050-060-040 magnetic chucks, a total of 200 magnetic suction block (Figure 1). Using an indexable insert with a 160-mm diameter cutter head, the vertically-mounted casting can be machined at 400 r/min speed and ap 3.5 mm lateral feed (Fig. 2). The weight of the workpiece is 200 kg. Magnos is a very effective clamping solution for shortening fixture setting times and improving machining conditions. The clamping method of magnetic clamping makes it possible to machine workpieces on five faces without the need for re-clamping adjustments. The whole process of the magnetic clamp is very simple, the ferromagnetic workpiece is placed on the clamp, the current is turned on, and a reliable electromagnetic force is generated after a few seconds. Even a discontinuously shaped workpiece can be firmly adsorbed in the magnetic clamp, even if Reliable clamping after power off (Figure 3).

Fig. 3 Since the workpiece presents a large area of ​​contact in the magnetic fixture,
Achieves vibration-free machining and extends tool life

Contrast test after using the magnetic fixture shows that the auxiliary adjustment time of the fixture can be shortened by 30%~50%, which obviously shortens the downtime of the machine tool. As a result, the investment cost of the new fixture can be recovered in a very short time.

Due to the large contact area between the workpiece and the magnetic chuck, the use of Magnos magnetic clamps can achieve almost no vibration processing, significantly prolong the service life of the tool; at the same time, it also greatly improves the surface quality of the workpiece during cutting. In addition, due to the large area contact between the workpiece and the permanent magnet fixture, the workpiece will not be clamped and deformed after clamping.

Schunk also produces a second-generation magnetic chuck with a magnetic suction block size 50. The distance between the magnetic clamper and the workpiece of the magnetic clamp increases, but the suction force of the magnetic clamp increases. When the magnetic suction block size is 50, each suction force can reach 105.6 t/m2. The structure of the magnetic chuck ensures that the magnetic fixture has a longer service life. The control components of the magnetic clamp system are very compact and extremely rugged, ensuring the need for normal start-up and shut-down operations.

Fig. 4 Display of magnetic clamp adsorption force, vertically clamped GGG 60 material workpiece

When adjusting the test run at the newly purchased machining center, EMA's magnetic fixture showed its strong performance (Figure 4). On the MFRI-050-060-040 magnetic chuck, a cast piece of GGG 60 material is mounted vertically. Lifting this kind of workpiece is a crane with a lifting capacity of 1.2 tons. Simple and quick workpiece clamping significantly reduces the number of auxiliary hours and fixed points. The almost no vibration and deformation-free clamping method improves the surface quality of the workpiece after machining. Magnos' magnetic clamping system satisfies all the requirements for machining ferrous metal workpieces. The electromagnetic clamping system provides high flexibility and economical use.