In the first part, we looked at some of the history of presswork and the various advantages and disadvantages of this method of manufacture.
In this part we investigate a few categories of parts you may be looking to produce and how Bracebridge Engineering would approach them:
A bracket required in high volume
A perfect product for pressing, dependent on complexity tooling prices can start from as little as £2000 and can pay for themselves in a very short space of time. The ideal tooling for this type of product would be what is called a progression tool or follow on tool. Progression tools aim to produce the final part in 1 stroke of the press by combining a number of stages in one tool that progress the part from a coil of metal to its final form. This ensures that the part is made as cost effectively as possible. The downside is a progression tool will normal cost a lot more than single stage tools where several operations are required to get the final part. As a general rule for volumes less than 10,000 a year single stage tooling offers a higher unit cost but is more less costly on the tooling side. So bear this in mind when you are considering the options. If your product is mild steel also ask what surface finish you require as BBE can supply in the following finishes:
- Raw state with anti-corrosion protection if required
- Zinc plated
- Tin Plated
- Powder coated
- Galvanised
- Wet paint + many more finishes.
- We can also manufacture using pre-galvanised steel.
Flat plate or 2D product
Some parts such as household window fixings, clamps, electrical boards, Network cable solutions and storage solutions require flat plate pressings with holes or sections cut as shown:
These can be made in high volume in the same was as a bracket however as no large forming is required the product is usually cheaper to produce and tool up for.
Bear in mind with 2D products in low volume, if tolerances are not too critical then these can be laser cut with ease and negates the need for tooling. Laser cutting is the chosen method for parts over 5mm thick. BBE would look to assist you with both methods and are always happy to suggest a method dependant on your needs.
Box shaped products:
If your part formed a rectangular or square box section, then again pressing is a great method of manufacture. The process in which this is done is largely the same as the bracket however in most instances a different process is needed. With some larger parts like car oil sumps a process called deep drawing is used. Ill expand on that process in the next part type. Box shaped parts can be produced using progression tools however their size tends to be bigger so always check with the manufacturer on this as some presses wont be large enough.
With regards to press size, the presswork company will do the necessary calculations regarding what size press is required to produce your product. BBE works closely with larger companies if we cannot accommodate a certain part and will always aim to help with any enquiry.
We manufacture the part shown in a number of stages on single stage tooling as this suits the customer and their requirements.
Cans, Pots and circular vessels:
Points to consider with drawn products:
- As can/pot diameter reduces in relation to can height the number of operations increase which increases tooling costs.
- High volume deep drawn parts need careful consideration of the method of production as tooling investment is high.
- Tight radiuses on parts makes the part prone to splitting so always allow the maximum permissible radii when designing your part.
- Some materials work harden when drawing and may need to be annealed part way through the process to allow further working, ask us if we think this is an issue. Stainless steel and Aluminium are common parts that need annealing when drawing.
- Developing the process on a new part can take time, tool trials and sample production can and does present problems which can cause delays so add a factor of safety in your lead times.
In the last part we'll look at some common issues that can occur when looking at pressing enquiries and some final thoughts on the topic.
For any presswork enquiries you may have, please contact
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