In the plywood industry, many consider the press line to be the heart of their facility. So much effort goes into getting veneers sorted, glued, stacked and ready to move into the towering presses that bind them all together.
The time and resources devoted to the press line make it very important to manage proper maintenance to ensure maximum efficiency and uptime. From hydraulic power units (HPU’s) and steam boilers to pre-presses, loaders, chargers, receiving racks and unloading systems, it is essential to have your equipment in proper working order.
Keeping your platens in good working condition is essential to press cycle times, proper adhesion of the veneer layers and ultimately the quality of your finished products. Your facility profitability can be impacted by how well you know the health of your platens. We are always available for a free quote, or any Platens questions.
Here are our Top 5 keys to ensuring your platens are working correctly, are energy-efficient and produce high-quality products.
1. Properly maintained boilers and clean steam
If you have steam platens, as most of the industry does, the quality of your steam can have a big impact. According to most manufacturers, regular maintenance to one of your most expensive pieces of equipment can pay off big and help troubleshoot potential platen heating issues. Scheduled purging of solids using a blowdown at least once a day can keep your boiler running efficiently and help eliminate particles clogging up your steam system. Some boiler manufacturers stress the need for proper feedwater quality going into your boiler as a critical element of reducing scaling.
Once the steam has left the boiler, keeping it clean, dry and pressurized on it’s way to the platen is very important. If you use Y-Type strainers, separators, or steam traps, keeping seals in good working order can help maintain proper efficiency.
2. Monitoring Platen Temperatures
It seems that most mills differ on when and where to monitor the temperature of their heated press platens. Most heated presses have Resistance Temperature Detectors (RTD) installed near their platens, to measure the temperature of the steam coming in or the steam leaving the platen. Some are installed close to the platen, while others choose to have them installed in the steam or condensate tubes. Using RTD’s on both sides of your platens may help troubleshoot issues of thermal conductivity within your platen.
At minimum, you should consider using RTD’s just below the crown, in the middle of the press and just above your bolster. A variance of more than 10 degrees Fahrenheit from the steam side to the condensate side may be a good indicator of thermal resistance problems. An infrared thermal gun or camera may also be a good additional tool to help measure the effectiveness of your heating system. Make certain that the gun/camera that you are using has a proper distance–to–spot (D:S) ratio.
3. Steam In, Condensate Out
As steam passes through your system, the thermal loss will occur, especially when pressure is inconsistent. When steam loses pressure, it cools and goes from a vapor back to a liquid state. The loss of thermal conductivity within the platen can cause a buildup of liquid and a difference in temperature from one side to the other on your platens.
This lack of uniform heat can leave the glue on your veneer improperly cured, causing the potential for delamination and other quality concerns. A common issue of liquid buildup in platens happens when the condensate tubes are taken off for maintenance and replaced with a different length tube/hose. The flow of the tubes/hoses must always be routed so that the liquid can make its way out of the platen and down to the bottom of the condensate trees with little resistance.
4. Platen Maintenance
Keeping your presses running at the optimum level requires regular inspection and maintenance. Making sure that a comprehensive plan is in place for your platens can really save a lot of headache and expense in the long run. With high pressures coming from inside the platens, and the exterior force of pressing the panels together, your platens go through a lot every single day.
When it’s time to inspect, pay special attention to these areas for signs of trouble:
- Inlet and Outlet Ports
- Window Plates
- Surface Condition
- Bracket / Hanger Mounting
- Operating Temperature / Pressure
- Nose Bars
- Release Agents / Cleaning
The frequency of maintenance varies from site to site. As a general rule of thumb, SparTek recommends platens receive full annual inspections and periodic inspection for damage every month.
5. Repair or Replace Your Old Platens
Significant consideration should be made to the cost of repair versus replacement. With repair, consider the cost of shipping the platen(s) back for inspection and repair, the cost of the time and materials to make the repairs and the cost to have it returned to your facility once repairs have been completed. If you have limited spare platens available for that press, you may be faced with running at less than full capacity for several weeks. It is also important to note that refurbishing your platens can reduce their remaining life down to 1-3 years.
If your platens are newer or in good general condition for their age and have not been previously reconditioned, there is a good chance that repair and refurbishing is a good option. If the platens are older than 12 – 15 years, have been regularly repaired, show signs of microfractures or have previously been refurbished, then it’s likely time for new platens.
As a leader in the platen industry for nearly 40 years, SparTek Industries has solutions to fit almost every circumstance. From inspection, repair and replacement; we can provide you with an evaluation of your system. Our platens are made to last with high-grade Steel, industry standard specification and a team of engineers that can properly fit new platens to your existing press.
If you would like more information about our platen services; please contact us at firstname.lastname@example.org.
About SparTek Industries
SparTek Industries, located in Portland, Oregon just a few miles away from the birthplace of the U.S. plywood industry, has been largely known (under multiple names) for producing some of the most durable and effective presses over the last 40 years. We understand the importance of your press lines and take pride in helping your facility running at peak performance. We offer systems that have stood the test of time as well as creating new innovations for the plywood and panel processing industry.