Many companies that outsource vacuum heat treating must eventually decide if they would be better served by setting up this capability in-house. Establishing a new heat treating capability requires a significant capital investment in furnace equipment.· However, there are other costs and issues that should be considered when assessing the business case for such a project.· VAC AERO has prepared a few brief guidelines to assist customers who are not well-experienced in heat treating but are assessing the need to establish a heat treating capability. (Download PDF of this article)

Furnace Selection – There are a number of factors that should be considered in selecting the best furnace equipment for a new heat treating operation.

 Size – Vacuum furnaces are available in a wide variety of sizes.  The initial capital outlay and operating costs are in proportion to size.  The furnace chamber must be physically large enough to handle the largest workpiece or load being heat treated, plus an allowance for tooling or fixtures.  To achieve proper heating and cooling in a vacuum furnace, individual workpieces within a load must be evenly distributed.  As a result, the furnace work zone may need to be slightly larger than what might be expected by someone unfamiliar with vacuum heat treating.  The furnace manufacturer can review the customer’s heat treating requirements and advise on the most appropriate size and orientation (horizontal, front-loading or vertical, bottom-loading).  When selecting a furnace size, some thought should also be given to future processing requirements.  It is usually impractical (and sometimes impossible) to enlarge a vacuum furnace if larger heat treating applications develop. 

 Budget: The basic equipment price for most popular smaller and medium sizes of vacuum furnaces will range from $300,000 to $500,000.  Additional costs will likely be incurred for site preparation and installation, auxiliary systems, tooling, staffing, and others.  These additional costs can be in the range of $50,000 to $100,000. 

 Throughput: The amount of work that can be processed in a single furnace load is proportional to the size of the furnace.  Typical vacuum heat treating or brazing cycles range in duration from a minimum of about five hours to much longer cycles, many in excess of twelve hours.  With allowances for loading and unloading time, only two to three complete heat treating cycles are typically completed in a 24 hour period.