Batch vs Conveyor Ovens

NEED HELP DECIDING WHICH INDUSTRIAL OVEN IS BEST?

It’s time to look for a new industrial oven when you have bottlenecks in your production line, or when you’re ready to start a new product line. Should the thermal process oven be a custom batch oven or an automated custom conveyor oven?

Curing, pre-heating, drying, bonding, or any other host of oven applications, all require one element — uniform and controlled heat. Both batch ovens and automated industrial conveyor ovens can provide those heating requirements, but which type is right for your operation?

To help you with your selection, in this article we will explore batch vs. conveyor ovens, covering the pros and cons, coupled with practical industrial process oven Guidelines.

To begin with, let’s operate under the following two assumptions:

• Business is good, work volume is increasing and there are bottlenecks forming in your heat processing areas of production.
• A market niche exists that you want to access and start a new product line.

In either case, you are faced with the prospect of spending thousands — possibly tens of thousands — of dollars on new heat process oven equipment to clear the blockages or begin production. The question near the top of your list is: “Do I batch the heating process, or do I purchase an automated industrial conveyor oven?”

A wrong decision could be very costly and time-consuming to correct, therefore, it is important to be aware of and understand the nine basic issues at hand.

1. Oven Cost
2. Oven Application
3. Allocation of labor
4. Dedication of space
5. Oven Cycle time
6. Quality control
7. Multiple temperatures
8. Product flow
9. Up-time

INDUSTRIAL OVEN COST

Cost is one of the most important issues a person can ponder before allocating funds to a capital equipment purchase. If you don’t have the proper financial backing, or if you are experiencing a temporary cash shortfall, “batching” your product can be a production lifesaver. A batch oven can keep you in the game until other business and/or production opportunities present themselves. Also, in terms of product or process, industrial batch ovens represent a comparatively inexpensive and economical means by which to enter or experiment in a new venture.

Conveyor ovens can be much more expensive to purchase initially. Consequently, an industrial conveyor oven is not as ideal for small-to-medium size start-up operations that want to experiment with a new method of processing product.

INDUSTRIAL OVEN APPLICATIONS

How do batch vs. conveyor ovens measure up in terms of oven application or usage?

Batch Oven – Are you to produce a wide variety of shapes and sizes, as well as multiple rates of production? If the answer is yes, then again, a batch oven may be the more appropriate process oven to purchase. This is simply due to the fact that industrial batch ovens are more versatile in what they can be “tuned” to accomplish, and they can process as much (or as little) as is placed on the cart, shelf or hook at one time.

Conveyor Oven – If you have large volumes of work with smaller pieces that only pose minimal differences in physical size, shape and physical composition, then an industrial conveyor oven may be a better choice, provided the funding is available.

ALLOCATION OF LABOR

Batch Oven – Labor allocation is something that can’t be overlooked because it plays an important part in your decision. An industrial batch oven, because of the racks and staging of those racks, almost always takes more manpower. Moving, loading, unloading, placing the rack in the oven, and pushing it to the next operation are all activities that take time, space, and precious manpower. Loading thousands of small parts, or a few larger parts, on a rack and moving them through production takes time.

Conveyor Oven – With a conveyor oven, it is quite possible to automate the entire production line, or at least large sections of it, to minimize the amount of time your workforce spends loading and unloading product. Your response to this factor will depend entirely upon business priorities and the labor situation.

DEDICATION OF OVEN SPACE

Batch Ovens – Take a hard look at the dedicated floor space available for the installation of your industrial oven. Batch ovens tend to have a smaller physical footprint than industrial conveyor ovens. This is especially true when the batch oven is in a cabinet or bench-top/stand configuration. However, larger batch ovens, such as truck and walk-in industrial ovens, can occupy the same, if not more, physical space than a conveyor oven. This is due to the presence of carts, shelves, and other special attachments that may be required to process product successfully.

Conveyor Ovens – The area occupied by an automated industrial conveyor oven needs just enough space to hold the oven itself and possibly a cart at the loading and unloading areas. That is, of course, if the unit is not integrated with other automated equipment, which would eliminate the need for peripheral components such as carts and shelving.

INDUSTRIAL OVEN CYCLE TIME

As you analyze all the factors, don’t forget oven cycle time. If the thermal process takes several hours or more, processing via a batch oven becomes much more attractive because the operator just leaves the parts in the oven for a longer amount of time.

However, with an industrial conveyor oven, the longer the thermal process or cycle time, then the longer the actual oven must be, taking even more physical space. Or, the slower the conveyor belt must run to meet the proper heat-up requirements. Some conveyors must run so slowly that they appear immobile except upon close scrutiny.

Using part size, production rates per hour and time factors, you can get a decent idea of what approach you ought to consider. See our Whitepaper page on Oven Cycle Dynamics for more information.

QUALITY CONTROL

With the development and increasing prevalence of international quality standards for industrial ovens, it is clear that mandates for ever-improving quality are here to stay. To meet quality control requirements at your operation, it is important for thermal processes to be controlled for minimal production variance. An automated line, once appropriately balanced, is more uniform on a daily basis due to the near elimination of the human element. Operators have less loading freedom and fewer timing decisions with an automated line.

Batch units can be loaded differently depending on the operator, and the actual cycle time may vary unless a ramp/soak programmer is used, which will reduce — not eliminate — this type of variance. However, in a majority of batch oven applications, any number of outcomes is possible with a human operator in control of the variables.

Below outlines the Pros and Cons of Batch Ovens vs. Conveyor Ovens.

MULTIPLE TEMPERATURE CONTROL

Batch Ovens – In the process of completing your products, you may need to ramp up with different temperatures and with different process times. Once again, batch ovens can be upgraded for this type of duty with the addition of a ramp/soak programmer, which can be a small investment in comparison to the cost of a total unit.

Conveyor Ovens – A continuous oven usually accomplishes multiple temperature and soak times via the integration of separate heating zones. This is also a very effective method of achieving the proper production end; however, such additions do add cost and size to the oven and do result in a more expensive endeavor.

PRODUCT FLOW

Batch Ovens – Product flow is another consideration as you answer the question, “How clean does my production flow have to be?” A batch unit does not always lend itself to extremely “neat” product flow. Usually, product is inserted at one end of the unit and retrieved from the same location. Of course, this scenario can be altered with the selection of a single or double door at each end of the industrial batch oven.

Conveyor Ovens – A flow-through conveyor oven is a cleaner type of unit because product is loaded at one end and can come out anywhere you wish, which facilitates operation flow. For example, an operator may load product and unload product at the same location, with the conveyor oven formed in a horseshoe configuration.

UP-TIME

Finally, there is an issue of paramount importance: Oven Care and Maintenance. Certainly “gremlins” tend to appear after some length of operation, but continuous up-time is critical. Batch ovens have fewer moving parts and are not as complex; hence, there is less to go wrong with the unit.

However, unless the process places a great deal of stress and is very hard on the heat treat equipment, the maintenance difference between batch ovens vs. conveyor ovens may not be significant enough to impact your decision. In this case, you would be better off giving more weight to the previous eight factors.

SUMMARY

Remember, the nine considerations listed here are general guidelines. They represent the starting point in your decision-making process as you explore the issue of whether an industrial batch oven or an automated conveyor oven is more appropriate for your operation. Naturally, the best support you can have is that of a high quality industrial oven manufacturer like Precision Quincy Ovens. Our experienced sales engineers can assess your production situation, assist you with process layout ideas and improve what will be your final production line. PQ Ovens also offers industrial oven Repair, Rebuilding and Retrofitting services.