MM. In the context of a company embarking on a micro manufacturing programme, what management issues will need to be addressed to ensure a successful project?

DB. DB. Most companies embark on micro manufacturing without a solid business plan and corresponding marketing plan. A business plan is critical for determining the financial strategy needed for a successful and profitable micro manufacturing company. Its surprising how many companies jump in before doing their homework, only to find that they aren’t able to service a major market segment.

MM. I have heard you quoted as saying that “you cannot make it if you cannot measure it." The metrology question in micro manufacturing is perhaps the most fundamental. Please give your views on this important area.

DB. In most cases, the micro manufactured component is the enabling component to creating devices. For this reason, measurement is extremely critical for validating the parts and processes used to manufacture them. Many micro manufacturers rely on ultra precision milling, micro EDM, and diamond turning machines to create tooling and finished micro manufactured products.

Once the precision components are taken off the workholding chucks, the registration to measure them is changed. Once the registration or datum changes, the error produced in measuring them is often 25-50% of the allowable tolerances, especially if the tolerances are measured in microns. If the parts produced cannot be measured appropriately, they cannot be validated, which in the medical arena for example, is especially important for implantable components.

MM. As companies move from precision engineering to micro engineering, do they start with a completely blank piece of paper, or can they utilise their expertise in the macro field?

DB. There are two parts to this question. One offers tool challenges and another offers cultural challenges.

Tools for Engineers. Tools for micro engineers are very different than those used in the macro world. For example, theoretical thermal and fluidic analysis for micro components and features requires the meshing of solid models with a completely different meshing model than those used in macro components. If models are meshed with typical “slices” of 10 micron nodes, the solid models will not represent what happens in between the 10 micron nodes. The creation of a much tighter mesh is required. Once the model is meshed appropriately (which can take hours or even days depending on the complexity of the features), only then can the meshed model be imported into off the shelf analytical software.

A similar issue exists in the micro moulding field, where micro moulds are required to create very thin wall (down to 30 micron) components. If the micro moulds are not in alignment to one another, the polymer will not flow evenly and therefore will have non fills — or even worse, freeze off conditions — causing costly micro mould core pins to deflect and break. Generally speaking, if the registration of cavity to core is higher than 10% of the wall thickness, the polymer will not fill the cavity.

Personnel. Macro experience is sometimes a positive and sometimes works against companies entering into micro engineering. Companies with long established views on creating micro geometry may be less open minded to trying new equipment, new tooling, and new ideas for creating micron level features and tolerances. On the other hand, all inexperienced staff may not be informed by previous experiences. The best is usually a blended group led and supported by open-minded management.

MM. A lot of people seem to be hung up on the question of "what is micro"? Surely, if a product is being made that is small or has small features that were previously impossible to make, and it services a demand in the market-place, it can be defined as micro. What do you think?

DB. DB. Micro is by definition 10 to the minus 5 and nano is 10 to the minus 9. Most define micro components as fraction of a gram, wall thicknesses of less than 200 microns, +/-10 micron tolerances, and having geometry seen only by magnification.

MM. There is a feeling that fixturing and parts handling are a key barrier to successful micro projects. What can be done to overcome this perception?

DB. This is absolutely true. Part handling, especially when the micro component is part of an assembly, is challenging. Fixturing to aid in assembly and/or measurement is key. Some fixtures can be purchased “off the shelf” but most are customised to fit the shape of the datum to assemble or measure properly. I would call this an enabling technology as opposed to a barrier, as this challenge can be overcome. The tooling for creating the geometry is one of the largest barriers to entry. There are very few micro machining companies capable of creating robust tooling and moulds for micro components.

MM. Micro EDM seems to be a technology that is emerging as very versatile and useful in the micro manufacturing arena. What do you see as the key role of micro EDM?

DB. Micro EDM is widely used in micro manufacturing for 3 major reasons: 1. Non-contact machining creates the least amount of metal material stress. 2. EDM works best with hard materials, thus creating a robust micro tool/part. 3. 3D shapes can be achieved with micro EDM.

MM. You will be presenting at the SME Micro Manufacturing conference in Boston, USA, in April. What will be the key focus of your presentation?

DB. My presentation is on high volume micro moulding applications. As parts become even smaller than dust specks, the use of micro factories will be important for assembling them. Holding onto a part with the same workholding chuck within a series of very small footprint micro stations will allow multiple materials and multiple processes to become integrated in one complete micro system. This is a trend that will continue with micro, MEMS, and nano components of the future.