Product category:
Power presses, mechanical
News Release from: Bruderer UK | Subject: Bruderer high-speed presses
Edited by the Manufacturingtalk Editorial
Team on 05 December 2002
High speed press to tighten
microstamping limits
One of the latest generation of high-speed presses has been installed at an electro-mechanical component manufacturer to research into microstamping components to finer limits.
One of the latest generation of Bruderer high-speed presses has been installed at the Portsmouth headquarters of electro-mechanical component manufacturer, Harwin, specifically for researching processes for microstamping components to finer limits, even though they are already accurate to within a few microns Another aim is to achieve this level of precision at higher production rates by developing progression tools that are able to run at speeds up to 2,000 strokes per minute (spm)
This article was originally published on Manufacturingtalk on 9 Aug 2001 at 8.00am (UK)
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In contrast, as recently as 10 years ago the industry was chasing +/-40 micron tolerances at maximum production speeds of 350 spm and with a tool life 30 to 40 per cent shorter than currently being achieved.
Alongside this R and D initiative, the company is investigating real-time quality control of components as they are stamped using a camera-based vision system.
It expects to have such 100 per cent inspection equipment fitted to the four Bruderer presses operating at Harwin's main production facility in Portsmouth by the first quarter of 2003.
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Two roll-type servo feed units designed to serve high speed presses working at up to 2000 strokes/min can accommodate irregular feed lengths or a version can be retrofitted to older presses.
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Re-use of tool sets high speed press automatically
High speed power press builder will be showing a 250kN machine at MACH 2006: it features a control system that allows automatic adjustment of ram stroke, coil pitch and punching speed.
The latest high speed press, which was purchased at MACH 2002, is a BSTA 200 (200kN / 2,000 spm) model fitted with the manufacturer's new CNC system, B-Control, which allows a 10-fold reduction in the time needed to set up the machine.
This speeds press changeover, reduces economic batch size and will allow Harwin to win lower volume, higher margin business.
Said company director, Paul McGuinness, " We started using Bruderer presses in the late 1980s when Harwin moved away from sliding-head micro-turning to take advantage of the higher accuracy and productivity achievable using fine stamping.
The Swiss press manufacturer was significantly ahead of the competition at that time in the field of high speed pressworking, particularly in the areas of bearing system stability and reliability of coil feed, and has remained in the forefront of this technology ever since." It was in 1995 that Harwin bought the first of its currently operating Bruderer presses, a 300kN / 500 spm model.
This was followed in 1998 by an 180kN / 1,000 spm press after McGuinness had visited another Bruderer press user that at that time was running its machines at up to 1,500 spm.
The other two presses in operation at the Portsmouth plant are two 180kN machines purchased in 1999 and a 250kN model bought the following year.
Continued McGuinness, "It became clear to us during the late 1990s that customers wanted faster component deliveries than we could achieve on new jobs because it took outside toolmakers typically eight weeks, and sometimes up to 12 weeks, to produce a two-blow progression stamping tool, which in our case has typically 14 to 18 stages.
"So we decided it to bring this function in-house and introduced our Fast-Track system to provide a total manufacturing solution and respond to customer orders faster.
As a large part of our export turnover is in the US automotive industry, this new approach was especially important as prompt delivery in this sector is crucial." By making each of the main elements of the tools the same size, such as the punch blocks, die blocks and bolster, Harwin has been able to achieve a seven day turnaround in custom progression tool manufacture as well as a 60 to 70 per cent reduction in tool cost.
Significant investment at Portsmouth in wire-cut EDM machines, camera-assisted grinders and 3D CAD stations has enabled this transformation.
The shorter lead-time in the production of metal stampings is mirrored in other departments; for example, rapid prototyping of moulded components is employed, and plating is faster by using coil mandrels that may be used on the output side of the presses as well as in the plating department.
The Harwin press facility now has the potential to produce up to 35 million components per month.
As a rule of thumb, presses capable of running at 1,000 spm such as the 180kN models are capable of one million parts per 8-hour shift when working flat out.
It is not difficult, therefore, to see the increase in profitability that will result from a doubling of stroking rate.
Some tools have already been taken out of production and run successfully at full speed on our R and D press, while others will have to be redesigned to achieve 2,000 spm.
Despite this being a mass production environment, as in other industries there is a need for shorter production runs to comply with customers' just-in-time delivery requirements.
The B-Control on the latest press has allowed Mr McGuinness to achieve a changeover time of 15 to 20 minutes, compared with typically three hours on the older machines which require rollers and cams to be adjusted manually.
In the case of the B-Control, it is simply necessary to input key parameters such as ram stroke, coil pitch and punching speed, and the press automatically adjusts itself using built-in servo drives.
Parameters for the tool are then held in the control memory, so set-up for a repeat job is achieved even faster by calling up the tool number.
A further considerable advantage of the latest Bruderer press design, according to McGuinness, is its ability to manufacture deeper components at any given stroking rate, resulting in greater production versatility.
For example, the new machine can operate at its top 2,000 spm speed with a tool stroke of 8 mm, whereas the 18 tonne presses can only achieve 1,000 spm with this amount of daylight.
At the latter speed, the new press can operate with a tool stroke up to four times larger, ie 32mm.
It is also noteworthy that, whereas earlier Bruderer presses were of three-pillar design, the BSTA 200 has four pillars to increase the accuracy of ram guidance and further prolong tool life.
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