Electric heating – Inductive heating – With workpiece support
Reexamination Certificate
1999-09-22
2001-09-11
Walberg, Teresa (Department: 3742)
Electric heating
Inductive heating
With workpiece support
C118S066000, C034S272000, C034S381000
Reexamination Certificate
active
06288377
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a varnishing oven. More particularly, the present invention relates to a varnishing oven design for a fan rotor manufacturing process.
BACKGROUND ART
Varnish is applied to automotive parts for a variety of well known purposes, such as improving part appearance, durability and performance. Although the primary purpose of a varnish coating is often for protection, varnish can also be used for noise reduction purposes, such as when used on various parts, including as fan rotors.
A variety of oven devices have been developed for applying varnish to parts and particularly to automotive parts. Conventional oven devices typically require the following steps: heating the part in an oven, applying varnish to the part, post baking the varnished part, curing the varnish, and cooling the part. The oven is often required to heat the part to a high temperature for extended periods of time in order for the varnish to be properly applied.
For example, for automotive parts, conventional varnish ovens typically take 15-20 minutes to heat the part to the desired temperature range for varnish application. This extended period of time is required to adequately heat the automotive part thoroughly to its core. If an automotive part is not heated adequately to its core, the temperature of the automotive part's surface will drop rapidly when removed from the temperature source. Any drop in surface temperature of the automotive part can result in unacceptable application or curing of the varnish. Heating the automotive part down to its core further requires extended preheating time.
This extended preheat time is undesirable since it requires additional energy and adds to the part processing time thus increasing the cost to manufacture each part. To compensate for this extended baking period, conventional designs increase the size of the oven in order to process larger numbers of parts at once. This increases productivity, but does so at the expense of oven size and energy costs.
Conventional oven size and cost is further increased by the use of post bake procedures. These procedures require further baking of the automotive part after the varnish has been applied. The varnished part is further baked to ensure that the varnish is adequately cured before the part is cooled. The additional heating further increases the cost, production time, and size of conventional varnish ovens.
It would therefore be advantageous to have a varnish oven that reduces the time and energy required to preheat, apply varnish and cure the varnish on the parts, reduces the size and cost of the oven, and reduces the cost to manufacture each part.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a varnish oven for use in a manufacturing process that minimizes the time required for an associated curing process. It is a further object of the present invention to provide a varnish oven for use in manufacturing processes that reduces the overall time required to process a part. It is a further object of the present invention to provide a varnish oven for use in the manufacturing process that reduces oven size, reduces oven cost and increases oven energy savings.
In accordance with the objects of the present invention, an improved varnish oven is provided. The varnish oven includes a preheating station using induction heating to quickly raise the surface temperature of the part and/or resistance heating to quickly raise the temperature of the windings to temperatures suitable for varnishing. The varnish oven includes a temperature homogenization station to ensure that a proper temperature is maintained across the surface of the part prior to the application of varnish. The varnish oven also includes a varnish application station where varnish is applied to the temperature controlled part, a varnish curing station where the varnish is allowed to set, and a cooling station where the part temperature is reduced. The varnish oven further includes an indexing conveyor to move parts through the oven stations and a control system for maintaining part temperature throughout the oven.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.
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Gruden Robert Steven
Nelson David Arthur
Shingledecker Joel Alex
Wu Zili
Drouillard Jerome
Ford Global Technologies Inc.
Van Quang
Walberg Teresa
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