User login

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

click an image below to view slideshow

Air cylinders on a machine also affect performance. Cylinders that leak do not fill with air as quickly and do not pressurize to their full capability. If air is leaking past the seals, then full pressure is impossible. For example, if a cylinder used for squeegee pressure were leaking, it would not press down as hard as normal—and cranking down the squeegee location would not correct the problem. Cylinders may leak because the rubber O-rings have dried out and cracked, thereby allowing air to pass. They can also move in the cylinder, causing intermittent leaks.

Electric
Proper grounding and surge protection is important. Its purpose is to guard your machine from acting unpredictably or losing its programming. Electrical storms and power surges have been known to cause machines to cycle on their own or to lose the memory stored in the PLC. Proper grounding and surge protection are important.

Safety is the most important reason to inspect your electrical systems (Figure 2). Most people assume that electrical service never changes and therefore should never need inspecting. They are wrong. Check to make sure that your equipment is fed power through the appropriate wire type and gauge and that the machine is properly grounded.

Inspect all power-feed connections for a solid connection, especially in flash applications where wires heat up and cool down a lot. Tighten these connections on occasion. Strain reliefs that hold the electrical cords as they enter electrical boxes should be inspected to make sure they have not come loose from moving a flash around. The stress these reliefs encounter can cause them to loosen.

Check wires for heat when the machines have been on for a while to see if excess heat is accumulating. The wire type and size you use must conform to local codes, but on occasion a machine is taken out and another is put in using the same cords. Checking loads with an amp meter when all machines are on at the same time is a good safety precaution. Your electrician should be brought in on occasion to check the load conditions and make sure circuit breakers are appropriate for the machines you have.


Terms:

Comments

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.

Watches

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

Did you enjoy this article? Click here to subscribe to the magazine.