Application of the Month
Drive Protection In Food Packaging
June, 2009 - View all Application Examples
In food packaging applications machinery cleanliness and corrosion resistance is of major importance. But not every application needs stainless steel. Sometimes other options are acceptable.
A new prospect contacted us recently looking to upgrade the performance and protection of the spiral bevel gearboxes they were using on their food packaging lines. Tighter motion control was becoming more and more important in their process so they were looking for a box with better consistency in rotary motion and lower backlash.
The second thing they were looking for was good corrosion protection. Since a majority of the machine’s components and structure were made of stainless steel they originally inquired what we had to offer in stainless steel gearboxes. Although we don’t presently have a standard line, we’ve produced custom stainless bevel boxes in the past for a variety of customers.
After we provided a quotation for the custom elements they at first desired the relatively higher cost prompted the prospect the re-think what it was they were trying to accomplish. Did they really need stainless steel or would other options achieve the goal they had set, at a cost that made more sense?
In their case the drive components were not actually in contact with any of the food products that were being packaged. The gearboxes were to be mounted under the machine and segregated by stainless steel plates and cover panels. So the need to protect against caustic washdown solutions was minimal. Most of the heavy cleaning was done to the top side of the machine where the food products were inserted and sealed inside the package.
However, the capability to periodically clean the entire machine and to avoid corrosion in the high humidity created after top side cleaning meant that protection options needed to be considered. That’s why a completely stainless gearbox was requested but ultimately deemed unnecessary when the cost exceeded the budget.
Most gearboxes are constructed with cast iron housings and carbon steel shafts and fasteners. Neither of these materials offer corrosion protection and, in fact, begin to rust rather rapidly in the presence of moisture. Cast iron can be painted to provide different levels of protection. Some of these options are adequate for general purpose protection although not for the harshest environments.
Unfortunately, in their application, painting had been a disappointing solution in the past. So they wanted to consider something different. Plus they really wanted a customized housing solution with as many of the standard holes and cavities removed to avoid the pooling of liquids that could result in bacteria growth. So this allowed us the opportunity to take a fresh look at the situation.
For our gearbox housings, bearing supports, and endplates, cast aluminum has always been an option. Being relatively soft, this material by itself really offers limited protection, although it doesn’t rust like cast iron. However, by subjecting it to a process called hard anodizing, the aluminum surface can be transformed into a harder material to provide adequate protection for a variety of washdown environments. For their application this solution was acceptable.
For shaft protection there are really two options. Stainless steel is best, but chrome plating is an alternative. Because the customer also had some custom shaft dimensions they were interested in, making them out of stainless steel did not add an outlandish cost over producing the unique dimensions in standard materials. It was only the material cost difference. So we were able to meet one of their original requests.
We completed the external protection package using stainless steel hex head bolts, instead of our usual socket heads, and added flat stainless steel oil filler/drain plugs top and bottom that were inserted with a two-pin spanner wrench instead of the large socket head plugs that are typically used. This further minimized water collection areas.
To avoid any risk of food contamination we filled the boxes with a synthetic food grade lubrication that was calculated to last well over 20,000 hours. This gave us a virtual lifetime lubrication rating which reduced the need for maintenance and lowered the cost of gearbox ownership.
The result was a gearbox that provided the corrosion resistance and protection options the customer ultimately wanted, included some stainless steel where absolutely necessary, and provided the customized dimensions that saved costs in integrating the boxes into the machine design.
While we offer all these customized features on as few as one unit, it is clearly more cost effective when there is a higher volume. This customer standardized on a couple basic models and set up blanket orders to take advantage of economies of scale. This made cost of acquisition more attractive, provided a better product for field service replacements of existing boxes, and offered enough design versatility to meet upcoming machine requirements.
Along with a wide range of standard gearboxes DieQua offers customized designs for most of the models in our product line. Its difficult to show all our capabilities in brochures or on our website. So if you don’t see what you are looking for or just want to see what’s possible, give us a call. We are sure to have a solution of your most demanding challenges.
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