Linear guides ensure long service life in the production of wooden pallets

Profile
 

• What was needed: drylin linear guides
• Requirements: Special environmental conditions, such as wood chips and dust, humidity, resin 
• Industry: Wood working
• Success for the customer: Longer runtimes under harsh conditions

Aloysius Krenzer KG manufactures Europool pallets and customer-specific wooden pallets with a high degree of automation. Founded in 1924, the company is one of the few pallet manufacturers which masters the entire process chain of pallet production, from the removal of long logs and sawing, manufacturing and processing up to logistics with its own vehicle fleet. Three of our own sawmills supply the basic products for the largely automated production lines. Several lines manufacture Euro pallets in accordance with EN 13689-1 and the quality criteria of EPAL, Krenzer's main product. In addition, the company also produces chemical, glass and customer-specific one-way and reusable pallets.

Problem

The dynamics of many drives with 50,000 strokes per day is very high. This applies, for example, to the handling units of the nailing station where the cover boards of the pallets are nailed. The machine itself removes all required wooden parts from the magazines and nails them together. The positioning of the deck boards is done by servo drives. The linear guides must be able to withstand the dusty environment  and alternating loads because the moving ends attached to the axes move up and down when they remove a board from the magazine. Added to this are the continuous vibrations caused by nailing.
 

Solution

The drylin bearings from igus prove their worth in linear drives that have to operate highly dynamically under heavy loads. Dry-operating drylin linear guides with iglidur liners ensure the precise guidance of the axes, which have diameters of 30 to 50 mm, which are ideally suited for the given conditions. The drylin pillow block bearings are also used in other plants in combination with hardened steel shafts. This is not the optimum friction combination recommended by igus, but it offers a significantly longer service life in this application. 4.5 million working cycles under unfavourable conditions. In Krenzer's experience, these linear guides have a service life of around three months. That doesn't seem like much at first. However, if you multiply 50,000 strokes by 90 days, this results in 4.5 million working cycles and that with dirt, high dynamics and alternating loads. And, most importantly: With other types of bearing arrangement, such as ball bushings and recirculating ball bearing guides, which Krenzer had experimentally used in other plants under similar conditions, the service life is even shorter. In addition, the guides operate maintenance-free under the unfavourable environmental conditions, and Krenzer is also very satisfied with the precision that the drylin axes achieve.