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A Review of Press-Maintenance Procedures

(February 2011) posted on Tue Feb 22, 2011

Find out how simple preventative maintenance can keep your presses running at peak levels and head off costly downtime and quality issues.


By Rick Fuqua

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Mechanical
A press’s mechanical functions are often unique to each manufacturer and, perhaps, to each model they make (Figure 3). Understanding how the basic functions work is key to understanding where to find wear and how to service the machine. If, for example, your machine uses a cam, it is likely that it will need grease. If a gearbox is used in conjunction with the cam, it will likely need oil. Knowing all of these grease and oil points is critical so they can be mapped out and assigned numbers. Numbering ensures that none is overlooked or missed.

Grease points are present in places of abundant friction (Figure 4). Reducing friction prolongs the life of the press. What is important to understand is that lubricants are often needed in areas where close tolerances are maintained. If a close tolerance is needed to ensure accuracy—registration, for example—then there may not be a lot of room to hold the needed grease. An example is the central bushings on a garment press. The tight fit of the indexer’s bronze bushings mated to the steel center shaft is critical to print registration. However, the design challenge is getting grease into this area and, more importantly, keep it in play for as long as possible.

In tight-fit scenarios, the grease always gets pushed out of the area where you need it. Operators see an abundance of grease that has been pushed out, and the sight gives them a false sense of security. What they are seeing instead is grease that is no longer useful. It has been pushed out of play.

In the example of the center shaft, a grease gun is required to shoot the grease into the groove cut in the bushing. When this cavity runs out of grease and it all ends up out of play, then the machine endures more wear than necessary until the cavity is filled again. Greasing these bushings properly is important. Check with your manufacturer, but normally I recommend rotating the indexer to 12, 3, 6, and 9 o’clock as grease is pumped into the bushings. This helps to distribute the grease.


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rocss says: Shop variables influence maintenance Figuring out how much downtime costs you is helpful. This stress test of how much downtime your shop can afford can help you determine how serious your action plan ...

Shop variables influence maintenance
Figuring out how much downtime costs you is helpful. This stress test of how much downtime your shop can afford can help you determine how serious your action plan of maintenance should be. Do your demands require production with critical deadlines every day? Do you have additional production capacity, such as a second machine or a subcontract relationship, if a problem occurs? Do you run more than one shift occasionally or regularly? Do the characteristics of your shop conditions or operation put stress on your need to maintain 100% capacity of 100% of your machinery all the time? The more stress, the greater the need for a proactive plan that entails trained manpower and a plan.

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posted on: Mon, 11/07/2011 - 9:27pm

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