Guide

The traditional approach to the manufacturing and assembling of small components and products is a combination of fabrication and machining processes. This is especially the case for the low-volume production of delicate parts where manufacturing tolerances are critical.

However, a viable alternative is to manufacture these parts by using deep drawing pressing operations. Deep drawn parts can be made to exacting tolerances, and often at a lower cost than is achievable by alternative methods. Deep drawing is feasible for small symmetrical parts that have a tubular or cylindrical shape. It is possible to stamp a wide range of materials, including carbon steel, stainless steel, copper, brass, silver and gold, to meet varying manufacturing needs.

Manufacturing Process Limitations

Although CNC machining centers are capable of producing parts of complex shapes to high tolerances, two major constraints exist. Firstly, the process is relatively slow as parts have to be machined from solid blanks that are larger than the final part, and, secondly, there needs to be sufficient material available to allow the part to be securely clamped. Another limitation is that the minimum wall thickness that is achievable is constrained by a combination of physical constraints and material properties.

A typical example of this problem is the cylindrical barrel of a pen or the inner and outer housing of tubular devices. An alternative way to manufacture such parts is to use specially drawn tubing of the right diameter and wall thickness, and to fabricate end pieces.

Both methods work, and an acceptable surface finish is attainable. However, these processes are slow, and costs are relatively high due to increased labor requirements. Additionally, once equipment is fully utilized, the ability to ramp up manufacturing volumes is constrained by the need to purchase additional machinery.

The Deep Drawn Alternative

In many instances, it’s possible to manufacture these same parts using deep drawn stamping processes. Current technology is capable of producing thin walled parts with a length to diameter ratio that exceeds 10:1, depending upon the material used. The wall thickness of the parts can be as low as seven-thousandths of an inch and critical dimensional tolerances as tight as one-thousandths of an inch are possible. These are almost impossible to achieve by other manufacturing processes.

Although deceptively simple, the design of deep drawn tooling is complex, requiring insight into material properties and deep drawing techniques. Typically, several stages of drawing are required to transform a flat, round blank into a hollow cylindrical shape. This is achieved by using multistage tooling with automated transfer systems so that one part is completed and ejected for each stroke of the specially adapted deep drawing press.

During the drawing process, parts are naturally work hardened and require no further heat treatment before use. In addition, deep drawn tooling produces an excellent surface finish that in many instances requires no further processing, especially if rust-resistant materials are used. Alternatively, parts can be coated in semi-automated processing machines or highly polished.

Increase Throughput and Lower Costs

Depending upon the size of the part, a deep drawn press can produce several thousand parts per hour. This is way above the output of comparable processes, and as a single stage operation, deep drawing greatly simplifies the assembly line.

The production cost of deep drawn parts is low, and although it is necessary to amortize tooling costs over the life of the part, the overall cost per part is almost always lower than parts produced by machining and fabrication processes. Apart from this, less material is used, tighter tolerances are possible and the final appearance of the part is usually better.

Deep Drawing manufacturing processes offers significant cost efficiency over other manufacturing methodologies. This is particularly true in cases where specific parts have complex geometries or require a high degree of precision and accuracy. Of course, even more cost savings can be achieved with the Deep Drawn process when simple geometries are necessary or parts are required to be seamless. When coupled with the fact that the deep drawing process can reliably be undertaken with a wide range of materials, the potential for cost saving on a per unit basis becomes apparent.

Effective Efficiency

In simplistic terms, deep drawing is a manufacturing process in which a material is drawn into the shape and configuration required. There are different dies and specific processes used by a variety of manufacturers but the process itself is efficient and more effective than traditional stamping techniques. One of the advantages and cost saving aspects is the deep draw process offers minimal material waste as opposed to extrusion or machining processes. Thus there is less excess material and little, if any, waste. When you consider the material cost effect, less waste means more material is going to the product thereby maximizing the efficiency of the material used.

Direct Effects On Costs

The direct effects on costs are numerous, in the ways of producing a low cost, highly efficient alternative to traditional part production. These include;

• Better Material Handling; Meaning less material required to generate a part over traditional manufacturing techniques.
• Higher Volumes lower the per unit cost
• Accurate and Precise Part Production; Less secondaries required, thereby lowering labor costs

While not specifically bearing on the cost analysis of Deep Drawn manufacturing, Deep Drawing has the advantage of producing parts that are tight tolerance, and require significant strength while having minimal weight characteristics.

Combined, all of the above create an opportunity for lower per unit costs as well as cost savings for a project, which becomes apparent in multiple part end products. Thus providing the opportunity to put a cost effective and efficient process at your disposal.

Despite global upheavals, the United Nations Industrial Development Organization (UNIDO) reports the manufacturing industry around the world is growing at 2 percent per annum. Indications are this will continue, with signs of a slight increase in 2016.

Most manufacturing growth is taking place in developing countries as well as in the Emerging Industrial Economies (EIE), which together are sustaining overall growth of 5 percent. Industrialized economies are lagging far behind, and despite initial forecasts of 3 per cent growth in 2015, manufacturing growth remains below 2 percent.

However, when the results for the industrialized economies are broken down, it becomes clear that East Asia, which incorporates Korea, Japan and the surrounding countries, is facing negative growth in manufacturing, Europe is struggling at just below 2 percent, while North American manufacturing is striding ahead at 2 to 3 percent per annum. What is also interesting is that both Europe and East Asia are only just recovering from a manufacturing recession that saw negative growth in 2012 and 2013, whilst throughout this period North American growth remained steady. China, which is grouped within the EIE, has continued to experience sustained growth rates between 7 and 9 percent.

According to the KPGM 2015 CEO outlook survey, business confidence in the U.S. is higher than overall global confidence. According to the report, North American companies are adopting aggressive growth strategies with particular focus on internal growth within North America. In Europe, manufacturing companies are still struggling to recover momentum following the serious banking and liquidity crises that hit that part of the world. In the Far East, countries such as Korea and Japan are suffering from lackluster internal growth exacerbated by strong currencies.

Although Chinese growth has slightly slowed, the country, along with other Far Eastern countries, still remains amongst the lowest cost manufacturing areas. Consequently, American companies are still continuing to offshore production to these countries, although there are signs that the trend may be slowing. One reason seems to be linked to a realization that “Next Shoring,” the manufacture of goods close to where they will be sold, makes economic sense along with shorter delivery times allowing for a faster turnaround time. Although this doesn’t mean that offshoring manufacture in the Far East will necessarily be cut, it does mean that the manufacturing industry around the world is seeking to manufacture products in regions close to where there is a demand.