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Custom Engineering
Modifications to Standard Parts

MDC’s technical sales engineers are available to discuss your requirements for any non-standard component. In the case where a catalog item may be close to your needs, but would benefit from a slight modification, the requirements could be easily noted using the existing catalog drawing. Locate the catalog page of the product to be modified. Provide the page number, a reference number if it’s available, and a brief description of the modification requirements along with a marked up copy of the catalog drawing. Product specific drawings are available for most products depicted in this catalog and are usually presented with the table for those products. 

MDC is equipped to build custom vacuum components of virtually any complexity. In the case where there is no standard component close to your needs, it will be necessary to generate a drawing. Custom components can be built to your exact specifications from a rough hand-sketch, detailed computer-generated engineering drawings or anything in-between. MDC uses AutoCAD® software and can receive drawings electronically in either DWG or DXF file formats. For a nominal fee MDC can supply a complete engineering documentation package on those projects for which drawings were not provided by the customer.

 

 Typical MDC custom multiport flange assembly

One example of the multiple ways to specify a custom component
The flange assembly at right depicts four popular methods of installing flanges in to a larger flange or plate. Del-Seal™ CF metal seal flanges have been used for the purpose of this example. The methods described would apply to most any flange type and configuration. The four methods of construction are referred to as standard tubulated, top flush mounted, zero length recessed and single piece integrally machined. These are given as examples for commonly asked questions. Discussing your application with an MDC technical sales engineer will help determine the appropriate solution for your application.

 

The tubulated method of construction would be one in which a standard or custom half-nipple is welded to the larger flange at the tube end. The larger flange or plate is counter-bored to match the tube’s inside and outside diameters. The tube to flange transitions are welded in the same fashion along the bore’s inside diameter. This method of construction allows the use of clearance hole, bolt and nut fasteners, and is the only configuration that would allow the use of a rotatable flange. 

 

The most economical method of installing a flange would be to use standard off the shelf components requiring the minimum amount of modification and fabrication or in other words a top mounted method. In this method the larger flange or plate is bored to match the bore size of a smaller flange. Both are then joined by fusion welding internally along the interface between the two bored pieces. In some cases, external skip welds are provided for additional mechanical strength. This is the most economical method of construction. 

 

The zero length method of installation is similar to the top mount method with one exception, the larger flange or plate is counter-bored to a depth that matches the thickness of the smaller flange. The counter-bore is used to reduce the overall thickness of the completed assembly and thus provides a zero length recessed profile. The flanges are welded in the same fashion along the bore inside diameter. This approach provides a more aesthetic look at a reasonable cost. 

 

An integrally machined method eliminates all weld joints, but requires the most amount of machining. Special machining steps include the use of blind-tapping for all bolt holes and off-center turning of the knife-edge seal geometry as well as through bore operations.  In some instances it may even be desirable to use helical thread inserts, since these would be easy to replace in the event a thread is damaged. Conventional threads would be very difficult to repair. This type of fabrication is the most aesthetic, but also the most expensive of the three choices.








 Related Topics
 Vacuum components made to order
 Chamber geometry