Milling instead of grinding

Increasing sustainability, efficiency and security are three important aspects when using the Maija milling discs. The sustainability is so outstanding that the Maija milling discs were awarded the German resource efficiency price in 2015.

The Maija milling discs are made of hard metal, and as such are completely recyclable. In addition, the milling discs can be sharpened up to seven times, and at the end, the no longer sharpenable disc still can be recycled. Each sharpen allows, depending on the processed material, a distance of up to 300 meters to be machined. The milling discs are intentionally made of hard metal and not of HSS, so that the cutting edges of the teeth slowly round off while the amount of material removed slowly decreases, but work can continue for a long time until sharpen is necessary.

Not only the milling discs are recyclable. While grinding produces metal dust, which is contaminated by the abrasion of the grinding wheel used, milling produces chips, which do not get contaminated with the abrasion of the milling disc. The produced chips may get vacuumed or picked up and get recycled as well. When processing magnetic materials, the collection may be done with any magnet, magnetic broom or similar magnetic tool. (Video (Youtube): picking chips with a magnet)

The dust free removal also has a positive impact on the machines used. As the work with the Maija milling discs doesn’t create dust, no dust produced while processing may get into the machine. Results are reduced maintenance costs and increased lifetime for the machines.

As already mentioned, the Maija milling discs have a substantial higher service life compared to common grinding wheels. Based on the increased service life, associated with a reduced amount of milling discs to be held on stock, the Maija milling discs are characterized by a reduction of the required storage space. The amount of milling discs required for an uninterrupted usage is calculated by the specific service life, as well as the time required for resharpen, which are currently four to six weeks. Having a service life of six weeks and four weeks required for resharpen, two milling discs are required to be able to work uninterruptible. This high service life also comes in handy when the milling discs should be integrated into (partially) automated processes. A frequent tool change in these processes may be very cost-intensive.

To use the milling discs, it’s not necessarily required to get new machines, even though it is highly recommended due to the technical characteristics. The recommended machines, hand angle millers, barely distinguish from hand angle grinders on the outward, but have technical and security-related differences. At first, the speed of the hand angle millers has been adjusted to the work with the milling disc. In addition, the machines have a special guard, to improve the security(Article: technical information about the Maija milling discs and the recommended machines).

While conventional milling with CNC machines is place bound, the Maija milling discs allow the usage with hand angle millers location-independent and on-site at the structures. This has a high potential to reduce costs when working on structures weighting tons, e.g. turbine constructions, as these structures no longer need a logistical complex transport to the processing location.

Previously we mentioned, that the removed material is not contaminated when working with the milling discs. The same is valid for the processed material itself, giving a metallic bright surface which prevents cavities when welding the areas processed with the milling discs. Thus, no time-consuming corrections at these areas are required. Alternatively, the Maija milling discs can be used to open areas perforated with cavities on point, and afterwards weld them flawless.

Besides cavities, grinding also causes structural changes and material discoloration. Working with milling discs prevents this, as the material only reaches a temperature of 40-60 °C, even after being processed for a long time. Due to the reduced temperature the risks caused by structural changes of the material are avoided too.

The low temperatures are also a result of the (almost) spark free work of the milling discs. When using appropriate milling tools, this is even possible on hardly rusting structures. (Video (Maija Frästechnik homepage): processing rusted rail steel)

Working without sparks massively reduces the effort for environmental protection. Caused by the special geometry of the teeth, the chips produced by the Maija milling discs might be picked up without gloves. This prevents e.g. already painted surfaces in the direct environment from being damaged by sparks or sharp chips.

Besides the advantages for the material, recycling and protection of the environment, preventing dust also got essential benefits for the health. In the case of dusts, there is a risk of forming explosive dust/air mixtures. How far and easily dusts spread can be seen in production halls with a high amount of grinding work, even in areas where no work is done. Grinding may cause so called “silicosis”, caused by the dust created while grinding on most materials, the consequences for stainless steel are even worse. While grinding stainless steel, respirable chrome and nickel particle are released, which cause lung disease like COPD or cancer. After knowing this, from the point of health it’s definitely relevant to prevent dusts, especially those containing respirable particles. Using milling discs prevents this as they produce chips instead of dust. Without dust, both, dangerous dust/air mixtures as well as unhealthy and carcinogenic dusts, get prevented. This doesn’t only protect the worker, but also all workers in range of the dangerous dusts.

Preventing dusts is not the only benefit for the health of the worker when using the Maija milling discs. Due to the self-weight of milling disc and machine the effort for the worker is reduced. The pressure used when working with the milling discs usually doesn’t exceed the self-weight of the milling tools. Therefore, the worker can focus on guiding the machine.

Another frequent health problem when using hand angle grinders are vascular diseases, which may be caused by the constant vibrations. Reducing these vibrations when working with the Maija milling discs is an important step to reduce the risk for white finger disease / VWF or vascular spasm. Presence of any of the above mentioned diseases doesn’t only affect the health of the worker but due to limited work ability and medical leave also has a direct impact on production and production processes in which the worker is involved.

While grinding, the loudness is disgusting for the worker and the environment. Milling helps here too, as the noticeable lower noise emissions spare the hearing of the worker, when working for a longer time, or any other worker in the direct environment of the milling worker.