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Cold Forging Basics

Riveting is one of the oldest forms of fastening.

Solid rivets have been found dating back to the Bronze Age (ended 800BC)

You will have seen rivets hidden in plain site on bridges, ships, Aircraft and Trucks to name a few common applications.

They are also common throughout your home, if you have double glazing then you will probably have our rivets in the hinges.

Rivets are formed by a process called Cold Forging, this process produces no waste as the head of the rivet is formed by upsetting the shank of the rivet. This ensures the grain flow of the material remains in-tact thus strengthening the fastener.

The rivets are inserted in the material to be fixed together and “set” by deforming the end of the shank of the rivet to product a permanent fix.

The more popular, semi-tubular rivet is set in a similar way but require a lot less setting load and provides a “Clinch” fix which pre-stresses the material.

Many engineers are unaware of the advantages or even the function of rivets, tending instead to fall back on threaded fasteners which are more widely available.

The most recent development in Riveting is the self-piercing rivet, where you do not need a hole in order to rivet two materials together. This process is now commonplace in state-of-the-art automotive manufacturing plants. JLR being pre-eminent in this regard.

The process used to produce these fasteners has been developed in order to use the same manufacturing technique, Cold Forging, but to enable finished components to be forged outright, with the same benefits, no waste and a very strong structural integrity.

We are happy to help customers or prospective customers with any queries that may have regarding riveting or cold forging. We have recently helped a number of companies by producing and riveting prototype designs for them.

We have been in this business since 1939, over that time we have provided innovative, low cost solutions to many fastening and cost reduction requirements, thrown at us by our customers.

In the first instance, contact me, Steve Hardeman either by e-mail (sales@clevdonfasteners.co.uk ) or by telephone on +44(0)121-378-0619

Productivity

Many pundits bemoan the lack of productivity in the UK. They may have a point but then again…

Measured productivity is the ratio of a measure of total outputs to a measure of inputs used in the production of goods and services. Source UK Gov’ Stats.

 

International Comparisons of Productivity – Final Estimates, 2016
Table 3: Constant price GDP per hour worked
2007 = 100
  Canada France Germany Italy Japan UK US G7 G7 exc. UK
1995 85.3 80.5 80.8 92.7 81.7 78.2 77.9 79.9 80
1996 85.2 81.4 82.7 92.9 83.5 79.4 79.8 81.4 81.6
1997 87.2 83.5 85.2 94.4 84.7 81.3 81.3 83.1 83.3
1998 88.6 85.8 85.9 94.3 85.3 83.4 83.7 85 85.1
1999 90.9 87.6 88.9 94.8 87.3 85.6 86.6 87.5 87.6
2000 93.5 91 92.7 97.7 89.4 88.4 88.2 89.8 89.9
2001 94.5 91.7 94.7 98.2 90.8 89.6 90.1 91.4 91.5
2002 96 94.5 96.3 97.8 92.7 92.4 92.3 93.3 93.4
2003 95.8 95.3 97.1 97.6 94.3 94 94.5 94.8 94.9
2004 96.5 95.9 98.4 98.1 96.8 95.4 96.9 96.8 96.9
2005 99 97.3 98.5 99 98.6 97.3 98.6 98.4 98.5
2006 100 100.1 98.9 99.4 99 98.9 99.2 99.2 99.2
2007 100 100 100 100 100 100 100 100 100
2008 99.9 99.3 100.1 98.7 100 99.3 100.6 100.1 100.2
2009 100.6 98.6 97.7 96.6 99.2 97.7 103 100.6 100.9
2010 102.1 100.1 99.8 98.9 102.5 99 105.6 102.9 103.3
2011 103.9 101.3 103.1 99.4 102.8 100.5 106.2 104 104.3
2012 103.6 101.6 104.1 98.9 103.6 100 106.4 104.3 104.7
2013 105 103.1 104.5 99.6 105.7 100.4 107.2 105.3 105.8
2014 107.6 101.7 105.1 99.5 105.7 100.3 108 105.8 106.4
2015 107.6 102.1 106.1 99.3 107.3 101.1 109.2 106.9 107.5
2016 108.6 103.4 105.7 98.4 107.6 101.6 109.1 107 107.6

Sources: OECD, Office for National Statistics

And there we have it in black and white, the UK’s productivity is worse than our international competitors with the exception of Italy. Case proven m ’laud…

This is where it gets tricky. The government statistics include services and the public sector. I am not clever enough to calculate the productivity of a service, but my experience of public services suggests that productivity is not high on their agenda.

As manufacturers, I am only interested in manufacturing (someone has to be!)
Contrary to widespread perceptions, UK manufacturing is thriving, with the UK currently being the world’s eighth largest industrial nation. If current growth trends continue, the UK will break into the top five by 2021. In the UK, manufacturing makes up 11% of GVA, 44% of total UK exports, 70% of business R&D, and directly employs 2.6 million people.
Source: The Manufacture

We are simple “metal bashers” (read some of our other blogs and you will realise we are much more than that, but it helps my case to keep it simple!). As far as I am concerned, productivity is the labour input against the productive output.

As you may know, My FD and I bought out our major shareholders in 2015. We started to seriously focus on Productivity towards the end of 2016.
I looked at various publications and went to a number of seminars on the subject. Most were by their nature, generalisations, many were purely academic exercises which bore no resemblance to the real world and I gained no new insights to how we may improve our productivity.

So back to basics, literally.

Our measure of productivity is labour hours against productive output (number of parts produced in our manufacturing plant, number of dispatches made in our warehouse)

We switched off half of our ERP system and re-wrote the key data requirement to enable our managers to have the information specific to them, that they used on a day to day basis, in Access. This had the effect of freeing up their time inputting information into the ERP system and saving time by them not having to trawl through reports to find the information they needed. We are an SME, this drastic course of action may not suit all companies, but it certainly helped focus departmental responsibility and accountability in the correct areas.

We focused on the simple things, why our overtime bill was static when in some months we didn’t meet our output targets, but when we exceeded them, overtime increased. OK I know you are reading this and saying “that wouldn’t happen here. Do the exercise, you might be surprised how many people come in early to avoid the traffic!

We shared much more cost information with our employees that specifically related to their areas, so they could see the costs rack up for little gain.

We employed a coach to work with our managers to ensure they managed and gave them the support to improve in areas that they recognised their weaknesses. This was a key move as the coach was not a member of the senior management team and was tasked with improvement not weeding out failing managers. Buy in to this took time but the results were better than I could have hoped.

Using 2016 as a base                                100%
Productivity 2017                                      107%
Productivity 2018                                      114%

This has resulted in higher profits, a lower break-even, better cash flow and less fire-fighting.

It’s a little like sport science, get the basics right and make small steps.

That’s our journey so far regarding Productivity (please note no employees were harmed during this process!)

If you have any queries or comments call me on 0121-378-6950  or e-mail me steve@clevedon-fasteners.co.uk

New Design Concept: Common Sense

The latest iterations of Computer Aided Design software now combine the traditional drafting facilities with structural, flow and performance, Finite Element Analysis. In theory products can be taken from concept to proposed solution, rendering, testing and performance simulation through to proposed manufacturing route. All of this within the software environment, reducing time, the need for expensive physical testing, resulting in a fully formed solution that meets the design concept envelope.

I’ve got to get me one of those!

With all this fire power, millions of line of code, NASA level mathematics and algorithms that could run a small planet, why, when the shiny new drawings land on my desk for quotation are they so ridiculous?

We are humble Cold Forgers (look it up) who spend our days making things, real world products. Daily we receive what can only be called “Designers Dreams”

Our many years of experience enables us and I am sure other engineering companies to quickly grasp the purpose of the drawings we are asked to quote on (the design envelope) we then look at the drawings from a manufacturing point of view.

We see tolerances that can only be achieved by grinding, mirror finishes on flat surfaces, holes that would need to be bored, not drilled, ground pins that are made from stainless steel inserted into steel bodies (thus creating a galvanic cell [look it up] resulting in premature corrosion failure) Body designs which need to be milled, the list goes on and on. Oh yes and by the way the purchasing department that has been tasked with the un-enviable task sourcing this product need to bring it in for tuppence.

At what point in the programme does the system say “seriously, are you sure you want to do this?”

The design works great, the computer said it would. Where is the button you press to cost all these processes and give you an idea of the piece part price?

Why does this happen?

How many great concepts have failed because of the computer said yes but real life said “for that price? no way”

Part of the reason lies in the way FEA was developed. If you look at a conceptual model below the right hand side has been neglected to some extent at the expense of the left hand side

We have tried a different approach. We take the design concept envelope and de-construct it. Working closely with the original designers, we propose alternative strategies to provide the same (or better in many cases) performance but within the cost parameters the product must meet.

Our Design Support Agreement provides a low cost, low risk method of looking at alternative solutions that didn’t come out of the box.

This is aimed at metal-based manufacturing companies, it isn’t for everyone but a short conversation and exchange of the relevant NDA’s will enable us let you know whether we feel we have something to offer

Contact me, Steve Hardeman on +44(0)121-378-6950 to discuss the matter further or e-mail me at sales@clevtec.com 

Also please visit https://www.clevtec.com/services

 

Designed to Fail

In this age of high tech, computer based design. A growing problem is becoming obvious to us here at Clevedon. As you know, whilst we do some very clever cold forgings and self-piercing products, our main business is based on the humble rivet. Solid Semi-Tubular and Fully tubular rivets. Some of you reading this blog may not even know what these products are or will confuse them with “pop” or other blind rivets

Therein lies one of the problems with modern design techniques. A confluence of two factors, demise of “old style” apprenticeship’s where some of our best engineering talent learned their trade and the rise of the computer savvy, iPad literate younger generation, many young designers have not been taught some of the most basic, fundamental engineering techniques.

This is not their fault, most CAD systems are great at producing designs drawings. Unfortunately, only certain techniques are included in the various wizards and “look ups” which mean that only certain outcomes will be produced.

Quite often these unintentionally, pre-defined outcomes are very difficult to productionise and more importantly very costly to manufacture.

We have had experience of being told by very well meaning designers that our suggested fixing proposal will not work because their Finite Element Analysis (FEA)testing show that the rivet will fail at a particular load. This despite that fact that in our long history (we began business in 1939), we have never encountered a failure mode of the type the FEA predicted would happen. To prove the point, we undertook practical testing to discover what happens in actual practice. The rivet did not fail.

Drawings are sent to us where in order to realise the designers dream, the product needs to be turned, milled, drilled, ground etc.  Each operation results in expensive individual set up and run times and thereby the final product is very costly to manufacture, at which point some very innovative designs are dropped because they do not make economic sense to peruse.

Powder printed samples are very good straight off the CAD system, but are incapable of predicting that the whole project will fail due to the lack of basic engineering input at the beginning. The old adage rubbish in, rubbish out, still holds true. All of these very sophisticated, technologically advanced  CAD and FEA systems all have the same fundamental, inherent weaknesses and results in the waste of large amounts of time, money and company resources, to say nothing of the potentially game changing design concepts that never come to fruition.

Here at Clevedon (the parent of Clevtec) we do not claim to have all the answers, but we are very good basic engineers. Having had to fight against overseas competition that has destroyed many good UK engineering companies we do have a very good track record in providing low cost, practical, innovative solutions to seemingly intractable design issues.

For the above reasons we have introduced a “Design Support Agreement” to work with designers to put some of the practical elements back into the design process that don’t come straight out of the can. We have found this has the most beneficial effect when we are involved early on in the design cycle but have also been able to re-engineer designs that have got into difficulty (usually cost difficulties).

Please contact us and ask for Steve Hardeman and we will very soon be able to let you know if we are able to help.

Engineering 101

Riveting is one of the oldest forms of fastening

Solid rivets have been found dating back to the Bronze Age (ended 800BC)

You will have seen rivets hidden in plain site on bridges, ships, Aircraft and Trucks to name but a few common applications

 

bridge

 

Rivets are formed by a process called Cold Forging, this process produces no waste as the head of the rivet is formed by upsetting the shank of the rivet. This ensures the grain flow of the material remains in-tact thus strengthening the fastener.

The rivets are inserted in the material to be fixed together and “set” by deforming the end of the shank of the rivet to product a permanent fix

rivet 1

 

The more popular, semi-tubular rivet is set in a similar way but require a lot less setting load and provides a “Clinch” fix which pre-stresses the material

rivet 3

Many engineers are unaware of the advantages or even the function of rivets, tending instead to fall back on threaded fasteners which are more widely available.

The most recent development in Riveting is the self-piercing rivet, where you do not need a hole in order to rivet two materials together. This process is now commonplace in state of the art automotive manufacturing plants. JLR being pre-eminent in this regard

Self_Piercing_Rivets_sketch[1]

The process used to produce these fasteners has been developed in order to use the same manufacturing technique, cold forging, but to enable finished components to be forged outright, with the same benefits, no waste and a very strong structural integrity

forg 1

 

We are happy to help customers or prospective customers with any queries that may have regarding riveting or cold forging. We have recently helped a number of companies by producing and riveting prototype designs for them.

We have been in this business since 1939, over that time we have provided innovative, low cost solutions to many fastening and cost reduction requirements, thrown at us by our customers.

In the first instance, contact me, Steve Hardeman either by e-mail (steve@clevedon-fasteners.co.uk ) or by telephone on +44(0)121-378-0619

PT Screws

Screw3

The growth in the use of PT Screws is driven in part by the need to reduce the total weight of an increasing number of component assemblies, either new design or redesign.

The type of plastic selected for the required component performance means that it is essential to use a fastener that maximises clench properties by ensuring high strip out torque values and in many applications prevents loosening due to vibration. PT screws are the ideal fastener for such applications where fasteners such as self-tapping screws for steel applications would fail due to their wide flank angles and shallow threads

Clevtec’s ever increasing range of PT screws manufactured at our two plants in Birmingham UK, currently cover 2.2mm up to and including 6mm diameter PT Screws in metric and imperial sizes (including Tri-lobe).

There are so many versions of PT screws available, we tend to manufacture to customers specific requirements

Ideally we would like a fully detailed drawing of what you require together with some idea of  the volumes you will be ordering

In the absence of a drawing, we need to know the thread size and type (Imperial or Metric), what type of head you require, Pan Head, Pan Flange, Countersunk, Mushroom etc. Do the heads need to be marked? what type of drive do you require for the screw, we can do manufacture most standard forms in common use

The trickiest area in the absence of a detailed drawing is heat treatment and finish. again there are many different requirements that can trip up the unwary. Is the product property class 10.9 or is it a through harden/case harden treatment? All our heat-treated parts that require zinc plating  (the most common finish) are hydrogen de-embrittled. The de-embrittling time can vary depending upon the heat treatment hardness that is specified

If you need any advice please call us

Screw1

 

Testing, Setting, Heat Treatment and other News

As you know, we manufacture Clinch StudsCD StudsWeld boltsBolt Loks™ etc. at our Great Barr plant in Birmingham UK. Like any manufacturer we take care to ensure the quality of our products, ensuring that every product is fully traceable from the base material through forging, thread rolling, heat treatment, plating, and dispatch. At Clevtec we try to go the extra mile. Our testing facilities enable us to ensure the performance of our products meets and in many cases exceeds industry norms.

clinch stud

clutch leaflet

Not working, could be your fault! What many of our customers don’t know is that the performance of the product is often compromised by the way it is set. Many products are set to a torque requirement, particularly in automotive

applications.

Many products are set to a torque requirement, particularly in automotive applications.

Did you know the torque performance could be reduced by 25% if the threads have any oil on them?

self_clinching_studs_stainless_steel

 

 

Don’t compromise on heat treatment

Many products are specified by customers to property class 8.8.

For those of you who are technically inclined, (ref. ISO898 Pt-1).

However, We heat treat our products to 10.9 property class unless specifically requested by the customer.

The reason for this is that 8.8 is on the cusp of needing to be de-embrittled. 320 VPN is the cut off point for products to be de-embrittled (250/320VPN below 16mm diameter).

To avoid any compromise regarding the quality of our products, we choose to heat-treat our products to property class 10.9 because at this level, hydrogen de-embrittlement is mandatory.

10.9 out performs 8.8 mechanically so the influence of lubricated nuts etc. is less significant. More importantly, in the unlikely event of a failure, hydrogen embrittlement cannot be to blame.

studs1SCS_FH


In other News………

The zinc and yellow passivation to be outlawed next year!

We are still asked to produce parts which are Zinc and yellow passivated. Some customers insist on this and will not take the zinc and clear passivation option. Yellow passivation will be outlawed in September 2017, there is some discussion around the certainty of this date but if a chemical supplier can develop a viable economic alternative with the same apparent colour (first across the line wins!)  Then the date will hold

Brake lining rivets and the American Clean Water Act

We produce copper brake lining rivets. These may be outlawed in 2021 as a result of the American Clean Water Act. An element of this act was specifically included in order to reduce urban runoff into San Francisco Bay. It has been estimated that 35/60% of urban runoff comes from brake shoes. The obvious answer is to change to steel brake lining rivets that are plated. The problem is that brake linings from countries that do not have rivet setting technology set the rivets by hand (not to be recommended, but it happens). The time line varies from state to state but manufactures are going for 2021. So what? I hear you say. Many environmental laws made in the US migrate to affect Europe; it’s as well to be aware

 

Cold Forging – What you should know

Knowledge of cold forging in British engineering circles is quite rare and even many engineering / design graduates do not know anything about cold forging.

The default production process for multi-diameter parts seems to be bar turning.

This is a great pity because, when compared to cold forging:

Bar turning can be up to 10 times more expensive

  • Bar turning is up to four times slower
  • A bar turned part is weaker than it’s cold forged counterpart due to grain boundaries being broken by the turning process
  • Bar turning produces a lot of scrap.

Here are some interesting facts about cold forging that you should know:

Cold forging is a net shape process i.e. the part has no scrap associated with it

  • Due to the net shape forging process, the grain boundaries are maintained and so it is inherently stronger than the equivalent turned part
  • Manufacturing speeds of up to 250 parts per minute are achievable
  • Cold forging uses wire to produce parts, commonly used materials include low and high carbon steels and boron (for heat treated parts), stainless steel (430,304,316) brass, copper, aluminium and aluminium alloys, and titanium
  • Great Cost savings can be made if we are involved at the beginning rather that the end of a design project
  • We produce 20 million parts per month for all kinds of industries all over the world from our two cold forging plants in Birmingham in the West Midlands
  • Our expertise in this area has no rival. The product solutions we can provide have the potential to save you production costs and help you to produce better end products.

 

Want to find out more about cold forging? :

Contact sales@clevtec.com or call me, Steve Hardeman on +44(0)121-378-5960

 

Watch this video to see cold forging in action: