One of the current trends in the manufacturing industry is the requirement of an MDR. This is the "paperwork" side of manufacturing and to some may be an unwanted impost to manufacturing. We see the MDR framework as inevitable and forces all manufacturers to maintain quality work. It gives us the opportunity to display the extra steps we already do to supply a quality product. As the name suggests we document the process involved in manufacturing an item. The MDR is tailored to suit what is being produced and concentrates on the areas of interest. For example let's say we are reporting on the manufacture of a variable speed drive (VSD) skid. The make-up of the skid will be a base, posts and roof. We have gates all round which gives the option of locking the high voltage areas whilst leaving access to the VSD. The main areas of interest would be the strength and durability of the skid base for transport and supporting the electrical equipment. The performance of the roof sheeting or the wire mesh on the gates is not included in the MDR. Generally an MDR for our VSD would have the following sections.
-Workshop/ General arrangement drawings.
-Inspection Test Plan (ITP).
-Non -destructive testing (NDT).
-Material Certificates/ Traceability.
-Welding consumable certificates.
-Pre- Delivery Checklist.
-Manufacturer Data sheets.
With our MDR we can document how we manufactured our VSD skid. The drawings include General arrangements and weld-maps which specify the sizes, materials, welding procedures and the welders who performed the procedures. We also supply an electrical schematic for these VSD skids.
The ITP specifies at the beginning of the project how we plan to make, test and collect information. Clients may have some input into the ITP and request to be present at certain stages of manufacture (hold points). For more demanding clients we need certain Inspection items signed off by a qualified person ie a welding supervisor.
Welding is highly regulated, For every weld specified on the workshop drawings we have a weld procedure produced and certified to AS/NZS 1554.1-2011 by a third party. Our welders are qualified in that welding procedure and are requalified biennially. Once fabricated, the critical welds like lifting points or main strength welds are tested. Magnetic Particle Inspection (MPI) is a form on non-destructive testing (NDT) which highlights any possible flaws invisible to the naked eye. If a weld is found to be flawed, it is ground out and re welded until it meets the standard.
The performance of the finished product can only ever be as good as the materials it is made from. To ensure the engineering was based on correct strength of materials, we require all of our steel suppliers to supply a Mill test certificate. We maintain a register of all steel purchased and how it was allocated to a job. This enables us to produce a steel mill test certificate for steel specified on the workshop drawing.
Our VSD skids are Hot dip Galvanised. This is done off site by a third party who supplies us with documentation as to the standard used. Some other products are painted, in this case the surface preparation and type of paint will be specified. The paint MSDS documentation will be included at the end of the MDR.
The Functional testing (FAT) is done once the equipment is installed on the skid. In the case of our VSD skids, clients regularly send technicians to perform their own functional testing. The object is to ensure the unit is fully operational when it leaves the workshop.
Before leaving the workshop we conduct a final inspection of the finished unit. We have a checklist which includes things like bolts tight, swarf removed, specified components installed, ready for transport etc. This gives us the opportunity to ensure our documentation regarding serial numbers and id plates is complete. It also helps us to maintain a complete set of hand tools :-)