Wednesday, September 4, 2013

Reverse Engineering and Mechanical Design

Reverse engineering is the process of discovering the technological principles of a device, object, or system through analysis of its structure, function, and operation.

As computer-aided design (CAD) has become more popular, reverse engineering has become a viable method to create a 3D virtual model of an existing physical part for use in 3D CAD. The reverse-engineering process involves measuring an object and then reconstructing it as a 3D model. 

Reverse engineering is also used by businesses to bring existing physical geometry into digital product development environments, to make a digital 3D record of their own products. It is used to analyse, for instance, how a product works, what it does, and what components it consists of, estimate costs, and identify potential patent infringement, etc.

Value engineering is a related activity also used by businesses. It involves de-constructing and analysing products, but the objective is to find opportunities for cost cutting.

Courtesy of Wikipedia.

This tool chest was produced by using SolidWorks and it is a true digital representation of the actual model, including its intricate lock mechanism and other features.

Detailed shop drawings and files were created for manufacturing and for patent purposes.

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Sunday, September 1, 2013

Air to Oil Powered Three Platen Press

Air to Oil Powered Three Platen Press product line is the most versatile of all the portable and modular presses offered by VorToolIt is well suited for steel rule die tooling, or to process e.g. aluminum extrusions, using multiple stations. 

This combination press / four post tool also called the "Three Platen Press" is accessible from all four sides. Multiple work stations can be mounted inside or around the perimeter of the press to utilize maximum usability while lowering the tooling cost per station at the same time.

• A wide selection of sizes available from a miniature of 4" x 6" inner work area to 36" x 36" or larger custom specified dimensions and anything between.

 Tooling could be mounted directly to the detachable transfer plates.

 The four post precision guide system ensures superior tooling alignment for punching, piercing, notching, blanking or forming.

 The power source could be as small as a 200 lbs capacity compact air cylinder for the smallest model, or it can be as powerful as your application needs it to be, using hydraulic power for up to 80 tons.

 The unit can be directly mounted on a bench top, or shipped with a dedicated stand. The stand could be anchored to the floor or have lockable casters for even grater mobility.

 The operator control is also fully customizable from our standard two push button system with anti tie down module* to a foot pedal, a pedestal style, or a non contact finger sensor system.

 As part of the custom options, when the part(s) are nested and are in the correct position, the press can be activated automatically. There may be a selectable PLC controlled operating system to cover all variations of your process.

 Safety devices are available from simple physical guards to light curtains to keep the operator(s) safe and meet any government or company standard.

 The material that is used for the press' components could be steel, aluminum or stainless steel, whether the press is used in a general factory environment, in a medical facility or in the food industry.

*Anti tie down module: It is a safety device that controls how the two push buttons function. The buttons must be pressed at the same time within few milliseconds. If one button pressed only or one button pushed after the other, the system will not activate. The operator’s both hands are occupied while the press is being activated and is in motion.

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Saturday, August 31, 2013

Box Frame Laboratory Press

Medium Duty Box Frame Laboratory Press

Light Duty Box Frame Laboratory Press

Box Frame Presses are offered by Vortool Manufacturing Ltd. and are the most suitable for applications with relatively low tonnage requirements. They are also suitable for laboratory and clean room environment.

• Some of the Box Frame Press models are very small in size, e.g. 8x12" foot print only.

• Both the inner usable area, height and tonnage could be increased to any specifications of your needs for up to 80 tons capacity.

• You may install any of your existing tools or Vortool Manufacturing Ltd. can design and build them for you, including the most precise and extreme tools that you will ever own. The Box Frame Presses can be equipped with different die mounting options for both the lower and upper die shoe from conventional to a time saving quick change method.

• Box Frame Presses are ready for bench top mount or shipped with a dedicated stand.

• Different operator controls are available to suit your needs.

• Depending of the environment where the Box Frame Press will be used, aluminium or stainless steel components can be used to build the equipment.

Hydraulic Powered Pillar Press

Pillar Presses are attractive for their ability to adapt easily for using different type, size or capacity power units that can be mounted on the top surface of the two upper railings. These models are best to be used with hydraulic power.

Pillar Presses are an excellent choice for budget oriented applications, yet high output or tonnage is required.

• Your existing blanking and or forming tools can be installed with ease, or custom designed tools may be supplied with the press.

• Operator control, mounting of the press, and safety devices are similar to the other presses and should be specified before ordering Pillar Presses from Vortool Manufacturing Ltd..

• The physical size and capacity of any of the presses may be specified, or can be chosen for you based on the project that you wish to use the press for.

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Air to Oil Powered "C" Frame Modular Press

The Air to Oil Powered C Frame Modular Press product line by Vortool Manufacturing Ltd. is commonly used for various purposes. The space saving and vertical style design make this unit attractive for different reasons.

•  The double sided C frame provides exceptional strength while maintaining the small foot print of about 5 inches wide only.

• The power source can be air, hydraulic or the combination of the two. The sample is equipped with an air to oil cylinder, using regular compressed shop air to operate. There are many models to choose from to suit most applications. The cylinders range between 1.5 to 12.5 Ton capacity. Other models are also available that are capable producing up to 60 tons at 120 psi air pressure.

• Conventional hydraulic cylinders can be also used for higher tonnage requirement. To keep the foot print to the minimum, high pressure hydraulic pumps and cylinders can be installed, capable for 80 tons output using a small, 5" bore cylinder at 10,000 psi.

• Tools or tooling components to be mounted on the horizontal platform. This press can be easily bolted on an existing bench top or shipped with a dedicated stand. These stands could be floor mounted or have lockable casters for even greater mobility.

• There are different operator controls to choose from. You can have a foot pedal or palm buttons with or without an anti tie down module. The control may be built pedestal style and can be equipped with non contact finger sensors to activate each cycle. Depending on the application requirement, a more sophisticated PLC integrated system is available.

• The above options are also available with the other press models such as the Box Frame Press, the Three Platen Press, or the Pillar Press.

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Strip Layout Design Concept for Metal Stamping

Strip Layout Design Concept for Metal Stamping

All metal stamping designs should start with the basics. A solid foundation is required with both a visual and technical guide to progress further.

The strip layout is the starting point of a design which is the foundation or plan to manufacture and build the actual tool.

The strip layout design has several purposes. Once complete, it gives a visual representation to the manufacturing facility and to the client to have a good idea how the tool will work and how each progression or step will be made once the strip or coil is inserted into the die. The stamping can then begin.

This visual guide is the most important aid for the designer. It reveals details to clearly see how each feature must be made at each progression as the strip advances into the tool. Then important decisions can be made to simplify the final design or make it fit for automation and most importantly to improve it before it even starts.

The strip layout should include punches, form blocks, pilots, and some die blocks in order to make it clear how the tool will work and produce the parts. It is to ensure that the tool will do exactly what it is supposed to do.

Designers who neglect putting enough effort into this process, often end up with design errors. As a result, the manufactured stamping tools don’t perform well enough or don’t work at all. In that case costly modifications are necessary to correct mistakes before production can start. Usually these tools are notorious for break downs and require maintenance more often than others.

The proper design of a strip layout gives a piece of mind to the designer to proceed in the right direction. It is insurance for the end user or those who finance the project and want to be sure that their investments are in good hands with the tool working efficiently for a long period of time without breaking down. This is what it is all about. The sole purpose of a metal stamping tool is to produce as many identical high quality parts as possible at the shortest amount of time without stopping. Every time the tool requires maintenance and is not producing, it takes money away and becomes less efficient.

A good tool starts with a solid foundation, a good strip layout that gives the chance to eliminate future nuances, and to build world class tools that you can count on.

Design Considerations for Stamping Tools

Design considerations or decisions are driven by a number of factors.

However there are a few mayor points that should not be missed and must be included in the decision making process. You could design and build an inexpensive fabricated tool or you could make one that is a top of the line master piece.

How do You Decide Which One to Make?
Your customer will tell you what they need, what material the stamped parts are, how many parts should be stamped, when they want the finished parts, and how much they are willing to pay and so on.

These are important guide lines toward the design. They tell you what you can do and what you can’t. They set some boundaries.

The part itself is one of the major contributors that guide you through what the minimum requirements are toward the tool. It will help you with what you need in order to produce the particular part.

You may raise questions that need to be answered. How efficiently will the parts be produced? How long will the tool last? How user friendly should the tool be? What are the variables that can be implement in the design?

The Above General Guide Lines Should be Specified More in Detail.
• How many parts will be produced per run, monthly or in the lifetime of the tool?

If the amount of production is low, you will know that the tool will likely be manually operated and be budget oriented.

If e.g. 5,000 parts are to be made every week for the next two years, than you know it is a high demand tool and automation and continuous operation is required. The tool must be designed accordingly. More time and money can be spent to make the suitable tooling.

• Low production rate equals inexpensive tooling components, unsophisticated guides, supports, etc.

• On the other hand if the tool is running all the time, then you will need to build a tool that lasts. It will require less frequent maintenance, and be built for high speed automation. The tool steel should be higher quality, and more suitable for extended use. In this case instead of using e.g. A2 or D2 material, consider using M2 with coated surfaces or Vanadis 4 Extra or comparable. For the extra cost, these tool steel will last many times longer before sharpening is required. Use a ball bearing guide system, instead of standard bronze plated bushings and standard die pins. The ball guided system is better for high speed punch presses and high speed stamping.

• Pressure plates require springs behind them to generate enough force. Consider using gas springs. They are generally suitable for high speed stamping, and about 250 spm and rated about 1 million strokes before servicing. They are also more powerful than conventional die springs with the same footprint. You can use punches with ejector pins in them to push off slugs that are serious obstacles in automated stampings. You can also use die buttons with slug control that keep the slugs in the die button, preventing slug pulling. Slugs pulled back onto the die surface area can jam the strip and cause the feeder to buckle the coil. If this happens, your tooling may be at risk for serious damage.

• Bending is generally done using a wipe form method. The parts eventually gull and have heavy marks. The form sections constantly require polishing, causing downtime and quality issues. Ready benders can eliminate most of these problems, where the bends have simple straight features. This method completely eliminates parts sticking into the form die, as they require less pressure and will not mark the part as much or just simply eliminate it altogether. It is a perfect solution for pre-painted strips to stamp.

• Stock pushers are designed for automated stamping and have a superior feature that make their use a preferred choice.

• At upstroke of the press, they release the force applied to the edge of the strip or coil entirely, allowing a resistance free strip advancement. The applied pressure is adjustable, and you can design the engagement timing as you need it. The pilot punches can locate the strip perfectly before you lock its position for the duration of the cut.

• Another contributor to your design is to know what press or presses will be used for stamping. Your tool must be compatible and fit the desired press or presses. You may want to consider making 3D models of the presses with the vital features that are necessary for your tool design.

• The general requirement toward any stamping tool and for their design is that it should cost as little as possible, yet produce the most amount of parts at the best quality, should not break down, and will last longer than the anticipated life span of the tool. This perfect scenario should be achieved at all times. Compromises sometimes must be made and accepted, but not be part of your design.

• The guide lines or restrictions that are set by your client, your manufacturing facility or your ability, will have an impact of the outcome of your design and ultimately of the stamping tools and the produced parts.

Custom Progressive Tool Design

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Portable and Modular Presses

Portable and Modular Presses

Air to Oil Powered "C" Frame Modular Press

Modular Press Using Multiple Punch Stations

Hydraulic Powered Pillar Press

Air Powered Box Frame Press

Air Powered Box Frame Press

Air to Oil Powered Three Platen Press

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iPhone App for Calculating Optimum Cutting Clearance for Metal Stamping

Cutting Clearance Finder iPhone App

Cost: $50 CDN

To calculate cutting clearance for metal stamping simply type in the material thickness and hardness of the stock that gives the calculated clearance per side and diameter.

Read this article about "Optimum cutting clearance for metal stamping".

If you are interested in purchasing this iPhone App please email VorTool.

Requirements for installing this app:
• Installation of FileMaker Go 12  for iPhone.
• Cutting Clearance Finder iPhone App is sent by email and will open up in your pre-installed FileMaker Go.

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Optimum Cutting Clearance for Blanking Sheet Metal

At optimum cutting clearance  for blanking sheet metal at any given thickness, the sheared edge or the shiny band should be about 1/3 of the material thickness. The ripped or break away surface is 2/3. 

This is an indicator that the bur does not exist or it is at its minimal.

When the band is too small, it indicates that the cutting clearance is too much. The bur is generally larger than normal, and the part may not be as flat as should be.

When the band is too large, it indicates that the clearance is too small. The bur is large and uneven, so the punch may stick in the strip and stripping is difficult. Die and or punch edges chip often. It is because the strip is extremely tight on the punch, and as it pulls out, the edge (weakest point) may rip off, especially when the ground surface is not as smooth as should be.

Generally I use 10% clearance per side between 1- 2.5 mm and 12-15% for thicker material. The thinner the material, the clearance gets smaller as well. Over time I collected data from cutting clearances and results, and I use this data as average in my calculations. There is a variable of soft, medium or hard material to be blanked. I developed an iPhone app to simply type in the material thickness and hardness of the stock that gives me the calculated clearance per side and diameter.

There is a misconception among toolmakers that absolute centered alignment of the punch and die is less critical when the sheet (stock or coupon) is thicker. This is wrong. When the components are misaligned, the bur is generally larger on one side and the other not. What happens is that the pressure required to blank, e.g. 40 tons, will force the punch out of its position and try to get back to the center. This deflection creates more problems than most people would think.

• Excess bur on one side.

• Flex, or movement while cutting. This movement will cut the life span (between sharpening by ~70%. Any side movement is the cause for most tooling problems.

• Excess strain on die components, guide pins and bushings.

• As a result of the above, the parallel movement of the die set is compromised and slightly tilted. This would compound the initial problem.

• The punch press will also suffer. The blanking pressure is shifting sideways and will wear off the press components sooner. The improper clearance also affects the tonnage required and is greater than usual. Used punch presses are generally worn and always have a little slack. It means that even a 200 ton press’ RAM could be pushed back for a moment before it can go down with full power. This slight hesitation also creates movement while cutting, and it is, again affecting the life of the punch and die edges. If this happens, the cut edge will look different. Sometimes the bottom edge can measure about the same as the upper part and the edge may have horizontal lines, small bands.

When I design tools, it is important for me that the tool stays in production as long as possible. It makes money. When the tool is off the press, it does not only require labour, time and money but will not produce anything either, and this is an even bigger loss. So, I always ensure that the clearances are correct and the alignment is absolutely centered, regardless of the thickness of the material. I use a similar precision for alignment between punches and dies, regardless if the thickness is 0.025 mm or 13 mm.

Monday, February 25, 2013

Stamping Dies and Cutting Clearances

I have been a tool and die maker for over three decades now. It still surprises me that a large number of toolmakers, designers and manufacturing companies for stamping tools do not fully understand the issue. Companies spend tens of thousands of dollars on all kinds of improvements, yet they ignore the basics, and the foundation of their business.

Metal Stamping and Manufacturing the Tools for Metal Stamping
The investment can be put toward training their designers and toolmakers to improve the bottom line. Making tools that last longer, and work longer before maintenance is required. I am talking about "Old School" professionals. They should know better and not make mistakes about the foundation of metal stamping.

The general rule is to make the cutting clearance 10% per side. That means when the stock thickness is e.g. 0.100 of an inch, the cutting clearance should be 0.010 of an inch per side. This 10% value is more like a guide only. If you don't know any better, use it. Just don't be surprised when the result is not as expected.

There are different materials that you can pierce or blank.
Put them in at least 3 different categories, such as:
• Low (soft), like copper, Aluminum, and plastics
• Medium, like CRS and Milled Steel, galvanized steel etc.
• High (hard), like spring steel,tool steel or other alloys.

The more carbon the steel has, the harder it is.

LOW - Often called mild steels, low-carbon steels have ~ 0.10 percent carbon and are the most commonly used grades.

MEDIUM - Medium-carbon steels have from ~ 0.25 percent carbon. Increased carbon means increased hardness and tensile strength, decreased ductility, and more difficult machining.

HIGH - With ~0.50 percent carbon, these steels can be challenging. There are even harder steels with 0.75 to 1.0 or more carbon content.

Because there are different metals to be pierced or blanked, with different molecular properties, the cutting clearances must be different as well. Do not ignore the facts. Get to know them to improve both the blanked parts and their tooling.

When the stock thickness changes within the same material, the cutting clearance needs to be different. If you punch two different sized holes in the same sheet, the cutting clearance should not be the same. Blanking and shearing have different cutting clearances as well.

There are at least 6 different variables that can tell you what cutting clearance should be used.
Improper cutting clearances have different results.
• The 1st and obvious is the excess bur on the blanked part. It caused by excess or too little clearance.
• Reduced punch or die life or premature wear.
• Punches and or die edges are chipping
• Die plate cracking
• Difficult stripping
• Deformed or rounded parts (not flat enough)

Improper cutting clearance will not only negatively effect both the finished product and tooling but the whole manufacturing process as well. Poor tooling must be taken off the press, components to be sharpened that create downtime, unwanted change in the process and loosing valuable time and money.

You may want to take a minute and calculate your loss when a tool is taken off the line. Is this happening often? There are tools that could be used for about ~15,000 parts between sharpening. Some tools will go for 500,000. I've seen two tools in my career that run millions of parts over the span of 20 years without the need of sharpening. I know this is extreme and the tool had other features that supported the long life.

My point is, that a tool  producing a large number of parts is not needed to be more expensive than the ones that perform poorly. They are simply made better to last longer and add more value to the end user.

I know it is not easy for everyone to know the details, or the variables that effect the cutting clearance. Each tool is unique with its own challenges, yet the same principles can be applied for best result.