The top 10 reasons for process improvement or new processes that require some type of heating, drying or curing include: increase in productivity through increase in system line speed, significant reduction in energy costs, decrease in maintenance costs, decrease in downtime, improve product quality thereby reduce rejects and rework, reduction of labor costs, reduction in floor space requirements, new product introduction, change in business owner or management, and/or to keep up with competition.
Electric and gas infrared (IR) heat processing is an exciting technology when implemented appropriately, however it is not right for every process. Is IR right for yours?
If you are looking to increase productivity, up to 80% of the time, adding infrared to the beginning of an existing gas or electrically heated hot air convection oven will provide a 30 to 100% increase in line speed and therefore throughput. Infrared heat is transferred directly to product coatings and product substrates and therefore much faster than convective heating because you don’t have to first heat the air.
If you are looking to significantly reduce your operating energy costs of your existing gas fired or electrically heated hot air convection oven, you can typically save from 20 to 50% of your operating costs due to the fact that you are transferring heat directly to the product coatings and/or substrates with minimal heat loss in air and without the need to purposely first heat the air before heating a coated or uncoated product. Also, in the case of powder coat processes, with an infrared preheat or boost at the entrance to an existing convection oven you are able to also turn up the air velocity in the first oven zone increasing the efficiency of the existing system as well.
You may be looking to reduce your maintenance costs and downtime. In particular, electric infrared systems are much simpler than convection ovens. There is no hot air heater house, no gas train and most of the time there is no air recirculation blower or air plenums. Therefore there are less components to fail, troubleshoot, preventatively maintain, and replace. Air temperatures in an infrared oven are also less or significantly less than a convection oven, resulting in less wear and tear on the oven structure and enclosure. The lower air temps translate into less time to get in and fix a problem as well. Infrared systems can be built somewhat modular. If and when heaters fail or are damaged, they can be (quickly) removed and replaced with a spare and then repaired off line to minimize system down time.
There is a lack of the necessity for moving air in most infrared heat zones or ovens. This helps minimize or eliminate the transfer of dirt or previously processed (powder) coatings to newly coated products being processed. This will help to improve product quality and minimize rework.
Better productivity can results in less labor costs. Most infrared (IR) heating, drying or cure oven systems produce better or significantly better productivity as a by-product of faster line speeds, and greater part density on a line production line.
Infrared helps shorten the heated oven dwell (time) requirements, usually significantly. Whether added as a boost to an existing line, or part of a new system IR or IR/convection combination system, the shorter heated dwell will result in less floor space required to do the same job as compared with what a convection oven by itself without any IR would require.
As companies develop and look to introduce new products, an existing systems capabilities are often stressed due to limitations that include work opening dimensions and/or line layout. It is not uncommon that a work opening, or conveyor turn radius in an oven is the limiting factor in a paint or powder coat system. These constraints can be addressed in many cases by the addition of infrared to provide more heated height, more heated length, etc. (the additional heat can even be timed with a photo eye or prox sensor permitting the turn on of the infrared heat only when needed for specific parts or work packages). You might even find that IR allows the overall heated dwell to be reduced to the point that a multipass oven configuration can be changed to a straight pass oven thereby allowing you to process longer parts than previously possible. Infrared’s modularity, flexibility and ability to be provided with fast response capabilities is critical to overcome these type of production challenges.
Changes in management or ownership may change a company’s production philosophies. Maybe your company has historically processed products to stock, and now prefers to go to a just in time processing, packaging and shipping operation. Maybe all of your products have historically been processed in one main (possibly wasteful) system, and now they will be produced in smaller, product specific, manufacturing cell systems. Using infrared to provide a time savings and in a much smaller footprint will help you and your company evolve to meet these needs.
Infrared will be useful in help your company keep up with their competition in a constantly changing marketplace.
Methods of implementing electric and gas infrared include:
- Infrared heating as a boost to quickly raise the temperature of coated product in front of or in the first zone of an existing hot air convection oven.
- Providing enough heated dwell to allow the heat/dry/cure process to take advantage of product substrate conductivity.
- The introduction of (non purposely heated) recirculated air movement to assist in the drying and curing in the hidden or recessed area(s) of parts.
- The introduction of true convection (purposely heating air) to help finish the drying and curing of coatings on products either following or right in the infrared oven section.
- Product rotation through the heated oven chamber.
- Multiple temperature control zones vertically, horizontally and in the direction of the conveyor or machine travel
Properly employing the above infrared oven design techniques will allow you and your company to meet process requirements in a cost effective, energy efficient, reduced footprint way that will result in successful equipment installations.
Based on the art of employing infrared in both process improvements and new requirements, it is highly recommended that you find an experienced company (such as ours) that manufactures infrared as well as hot air convection ovens and systems and whose primary interest is in finding and recommending the best solutions(s) for your process improvements and new projects, no matter how small or large they may be.
Background: David Weisman, L.L.C. designs and manufactures gas & electric infrared heater/control packages, and infrared, hot air/convection & combinations ovens and spray booths for a broad range of industrial heating, drying and curing applications for individual metal, plastic, wood products and and paper, film, foil, textile, continuous webs, wire and cable extruded rubber products. Conveyorized and batch ovens and turn-key systems. Automated or batch processes.