Buying a Wire EDM: Speed, Accuracy and Finish

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What kind of surface finish can the purchaser of a wire EDM expect with today’s technology?

 

The two things every wire electrical discharge machine (EDM) user wants are speed and accuracy. Unfortunately, these objectives are usually incompatible. You don’t get speed with precision, and you can’t achieve high accuracy without also achieving a fine surface finish. Accuracy and surface finish go together. Speed and accuracy do not.

 

Cutting Speed, Accuracy and Surface Finish

EDM units from the early 1980s might achieve cutting speeds of 3 to 4 square inches per hour. With changes in machine design and power supplies, speeds of 17 square inches per hour became attainable in the 1990s. Today, with improved power supplies, working in conjunction with sophisticated adaptive controls, it is not uncommon to achieve 24, 37 and in some cases 45 square inches per hour.

 

The type of material and the height of the part being cut are critical as well. It is generally easier and faster to cut hardened tool steel than cold-rolled steel, for example. The harder material is the better. Typically, tool steels, carbide and special alloys have fewer impurities and lower porosity, making them easier to cut. Cold-rolled steel may contain impurities, so wire cutting is slower, and the surface finish is poorer. Although aluminum is easy to cut at higher speeds, the material is so soft that it is very difficult to get a good surface finish. Even a 30-microinch surface finish is difficult to achieve in aluminum. In contrast, it is possible to cut a 3-inch-thick carbide workpiece, with accuracies of ±0.0001 inch, and still produce a of 5-microinch Ra surface finish.

 

A typical wire EDM process consists of several passes, traveling at varying speeds. The first pass is generally a roughing pass designed to cut as quickly as possible, while accuracy and surface finish are less of a concern. Each subsequent skim cut travels at progressively faster speeds, takes less and less material while steadily improving dimensional accuracy and quality of the surface finish.

 

During the finish cuts, the tension on the wire is increased, the current is reduced, and the voltage gap narrowed, allowing the user to refine the spark and the distance the spark jumps from the wire to the part. The offset applied to the last finish pass might be as small as 3 microns. To achieve a 4- or 5-microinch Ra finish, as many as six or seven skim cuts might be necessary. Whereas the diameter of a cutting tool determines the offset in milling, the EDM controller applies a cutter comp based on the diameter of the wire. For example, if a 0.010-inch-diameter brass wire is used, the cutter comp will approach 0.005 inch plus a spark gap as the wire gets closer and closer to the part surface, and possibly finish at 0.0051 inch.

 

To achieve these close tolerances and super-fine surface finishes, every parameter must be properly set. The right type of EDM wire must be selected. The wire must have the right diameter and tensile strength. The power setting and tension of the wire must also be right. The condition of the deionized water and flushing arrangements must be optimized, as well.

 

Machine Accuracy

When attempting to hold ±0.0001-inch positional accuracy with wire EDM, the shop environment becomes a factor. For example, both steel and carbide have a thermal expansion coefficient of ~6.8 ppm per degree Fahrenheit. This means that, for every 2°F change in shop temperature, a 12-inch part could grow as much as 0.00016 inch, putting the operation over the 0.0001-inch tolerance it is trying to hold. To be successful under these conditions, a shop must be able to hold its ambient temperature within 1°F in either direction during an eight-hour period. Controlling the temperature of the dielectric solution to ±1°F also helps control the temperature of the machine and the workpiece.

 

The two most common machine designs use either ballscrews or linear-motion systems. In terms of machine accuracy, each design has pluses and minuses, which must be explored when choosing a wire EDM unit.

 

High-precision glass scales are used to negate the effects of pitch error or backlash on the linear feedback. On the best machines, high-resolution servodrives with fine increments are used to position the wire, thus improving surface finish and accuracy. Adaptive controls can compensate for thermal growth. High-speed circuitry in servomotors enables them to react instantaneously for finer control of the spark. High-peak power supplies can now put more electrical energy into the wire, greatly enhancing productivity.

 

If you need more information of EDM machine manufacturers, I sincerely recommend you to visit Excetek Technologies Co., Ltd. – the company specializes in manufacturing high-quality EDM machines. To get more details of EDM machining, welcome to check out their website and feel free to contact with Excetek!

 

Article Source: https://www.mmsonline.com/blog/post/buying-a-wire-edm-speed-accuracy-and-finish

Machining Performance Reveals Opportunities for Efficiency Gain, The Value of Tooling Choices That Save Time Will Be The Important Key

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As more sophisticated insight into machining performance reveals opportunities for efficiency gain, the value of tooling choices that save time will become increasingly clear.

 

The promise of Industry 4.0 is great news for the adoption of advanced cutting tools. The reason: In interconnected manufacturing systems in which comprehensive data reveal the performance of the system, the impact of an advanced tool becomes clear.

 

Historically, the lack of clarity about manufacturing performance has been the main impediment to shops embracing high-end cutting tools. Tools typically account for just 3 percent of the per-piece production cost of a machined part. However, a tool’s price tag is more visible than its benefits. This fact leaves manufacturers frequently pursuing cost-saving steps that have little impact. For example, at 3 percent of unit cost, finding tooling that is one-third less expensive will only cut the per-piece part cost by 1 percent. Something similar is true of tool life: Even doubling tool life will only cut cost per part by 1.5 percent. However, finding tooling that provides for significantly faster machining or reduced non-cutting time enables each unit of machine and labor time to deliver more parts, likely cutting the cost per piece by 10 or 15 percent.

 

This argument makes sense in the abstract. The problem is, it can be hard to marshal the data to prove this case as it applies to a specific tool in a specific cut. That is where Industry 4.0 comes in. We are moving into a world in which manufacturing systems increasingly do marshal data such as this, and manufacturers increasingly make use of it.

 

To get more efficient cutting tools, come and visit Shin-Yain Industrial Co., Ltd., they can meet all your requirements of cutting tools.

 

Article Source: https://www.mmsonline.com/blog/post/iscar-leader-describes-tool-technology-for-machine-shops-acting-on-data

What’s The Best Type of Gearbox for Servo Applications?

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Gearboxes provide torque multiplication, speed reduction, and inertia matching for motor-driven systems. Servo systems, specifically, require gearboxes that can supply not only high torque with low added inertia, but also high precision and stiffness. One type of gearbox meets all these criteria while providing relatively long operating life with low maintenance requirements: the planetary gearbox.

 

A planetary gearbox consists of multiple planetary gears, which revolve around a central sun gear while engaging with an internal gear and rotating on their own axes. The continuous engagement of the planetary gears means the load is shared by multiple teeth, allowing planetary designs to transmit high torque loads.

 

This load sharing among teeth also gives planetary gearboxes high torsional stiffness, making them ideal for processes that involve frequent start-stop motions or changes in rotational direction, which are common characteristics of servo applications. Most servo applications also require very precise positioning and planetary gearboxes are designed and manufactured to have low backlash, with as little as 1-2 arcmin in some cases.

 

Planetary gearboxes can use spur or helical gears. While spur gears can have higher torque ratings than helical gears, helical designs have smoother operation, less noise, and higher stiffness, making helical planetary gearboxes the preferred gearbox for servo applications.

 

When a gearbox is added to the drivetrain, the rotational speed delivered from the motor to the driven component is reduced by the amount of the gear ratio, which can allow the system to make better use of the servo motor’s speed-torque characteristics. Planetary gearboxes are able to accept very high input speeds and provide speed reduction of up to 10:1 for standard designs, with high-speed designs providing gear ratios (and, therefore, speed reduction) of 100:1 or higher.

 

Planetary gearboxes can be lubricated with either grease or oil, although a planetary gearbox for servo use (sometimes referred to as a “servo rated” or “servo” gearbox) is often lubricated with grease. In either case – grease or oil lubrication – planetary gearboxes are often lubricated for the life of the gearbox by the manufacturer, which eliminates maintenance for the end user.

 

The most important benefit of using a gearbox in a servo system is arguably its effect on the inertia of the load. The load inertia, which is reflected to the motor, is reduced by the square of the gear ratio. So, even a relatively small gear reduction can have a significant effect on the inertia ratio.

 

While a “perfect” inertia ratio of 1:1 is impractical in many cases, the goal of most servo system designs is to keep the inertia ratio as low as possible in order to achieve high system responsiveness. Reducing the load inertia by adding a gearbox to the system means that a smaller motor (with lower inertia) can be used, while still maintaining a desirable ratio between the motor and the load. And a planetary gearbox, by virtue of its compact design, has a low inertia itself, adding only a small amount to the load inertia that the motor must balance.

 

If you want to get more information of servo gearbox, I recommend you to visit Jia Cheng. It is a professional manufacturer of reducer, gearbox, and coupling. To get more details, welcome to check out their website and feel free to contact with Jia Cheng Precision Machinery Co., Ltd.

 

Article Source: https://www.motioncontroltips.com/whats-the-best-type-of-gearbox-for-servo-applications/

How to Choose The Right Casters & Wheels?

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It’s surprising how many industries rely on casters and wheels to facilitate their day-to-day operations; they’re the unsung heroes of the working world. You’ll find casters and wheels in any number of environments, including warehouses, offices, hospitals, restaurants, and retail departments; they ensure that loads, such as deliveries and equipment, can be efficiently moved around the workplace by employees without much physical effort.

 

However, choosing the right sets of casters and wheels for each of these environments is not an easy task. There are a number of things to consider when distinguishing between product types, which could be the difference between having a solution that works effectively and one that could be detrimental to productivity – in many cases, choosing the wrong casters and/or wheels can prove very costly.

 

In this guide, we share everything you need to know about selecting the right casters and wheels for your needs.

 

Does It Really Matter Which Casters & Wheels You Choose?

Yes, it does! Here are just three ways the right (or wrong) casters can make a big impact on your business:

 

  • Ease Of Use – The right casters and wheels can do wonders for day-to-day productivity; the easier the product is to use, the quicker tasks are completed. Likewise, the wrong caster can make moving loads extremely difficult, leaving workers feeling frustrated.
  • Safety – Not only can bad casters make work slower, they can also make moving heavy loads quite dangerous. If a caster is too stiff, doesn’t swivel properly, or isn’t designed to adequately support the load, there is a risk of workers over-exerting themselves or even becoming injured if the load falls.
  • Floor Protection – Heavy items can damage the floor when being moved if you don’t choose the right material for your wheels.

 

What to Consider When Choosing Casters & Wheels?

In order to avoid any of the above events, you need to make sure you’re choosing the right casters and wheels for your work environment. Here are some of the most important aspects to bear in mind:

 

  • Wheel Diameter: Larger wheels make a load easier to move, so try to choose the largest wheels possible, without increasing your load’s center of gravity; this can cause the load to tip when being moved.
  • Rollability: Different materials have different levels of rollability, so it’s important to consider what’s right for your load. Plastic wheels are easier to move, but they will also pick up momentum much faster – if you have a particularly heavy load, you want to ensure that workers will still have control if it’s moving at speed. Rubber wheels are harder to move, but they do offer a degree of control.
  • Swivel Radius: You’ll need to decide whether you want a caster with swivel capacity. This would allow workers to navigate corners more easily, but would also require more control.
  • Brakes: There are two main braking options to choose from: friction brakes and locks. A friction brake offers users more control over the speed of a load when transporting it; this might be useful in environments where loads are moved amongst the general public, like hospitals. Locks prevent the load from moving when left unsupervised.
  • Load Capacity: Every caster is designed to support a maximum weight. It is crucial to stay within the maximum weight load so as not to cause damage to the caster itself. As a general rule, additional casters can increase the maximum load capacity of a cart or trolley.
  • Mounting: When mounting your caster, you can choose from two different options: top plates, which are attached to the cart or trolley surface using a bolt, and press threads (or screw threads) which are attached via an insert.

 

If you need more choice of chair caster wheels, welcome to visit Enjoying Go Co., Ltd. – they are the professional manufacturer of various caster wheels. You can find office caster wheels, locking casters, medical casters, design casters and much more products there. To get more details of caster wheels, please do not hesitate to contact with Enjoying Go!

 

Article Source: https://www.sinclair-rush.co.uk/news/how-to-choose-the-right-casters-wheels/

Choosing the Right Metal Hole Saw

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Hole saws are cylindrical cups with a serrated edge to cut various sizes of holes in a variety of materials. The serrated edge is designed to cut the hole; the other end is designed to be driven by an arbor or drill chuck. There is a wide variety of hole saws available in the marketplace, from inexpensive carbon steel hole saws to extremely specialized, application driven hole saws. The most commonly used saw, however, is the bi-metal hole saw.

 

Advantages of Bi-Metal Hole Saws

Most users prefer a bi-metal hole saw for the majority of their work because it is compatible with a wide variety of materials. It also cuts faster and smoother and with reduced vibration due to the variable pitched teeth.

 

Hole saws have two different types of steel joined together to form the edge of the cutting end of the hole saw. High speed steel is joined to a soft spring steel to form a durable edge that will cut a multitude of materials and help provide long life. High speed steel is used on the outer edge due to its wear resistance properties and forms the cutting edge of the teeth. Soft, spring steel creates a flexible backing material that allows the hole saw to absorb impacts of the job of drilling holes in difficult-to-cut materials.

 

A good bi-metal hole saw will easily cut through softer materials, such as plastic and wood-based items, as well as harder materials, such as steel and stainless steel. The type of high speed steel chosen by the hole saw manufacturer will contribute greatly to the performance of the hole saw. The best bi-metal hole saws will be made with high speed steel that has a high percentage of cobalt content.

 

More important to users is the life they will get from their bi-metal hole saw, or how many holes they will be able to cut before needing to replace it. In addition to using high speed steel with cobalt, the heat treatment process used by the manufacturer will impact the life expectancy of the hole saw.

 

One common frustration users have with cutting holes with a hole saw is removing the plug, or slug, from the cup after the cut is complete. Look for slots that are accommodating to easily work the plug from the cup.

 

Tips on Arbors and Pilot Bits

Cutting a hole with a hole saw requires the use of an arbor and often a pilot bit. Arbors, also called mandrels, are designed to connect a hole saw to a drill chuck as well as hold the pilot bit. They are made from hardened steel and alloy steel components for long life, as they need to last through multiple hole saws. Arbors connect to the hole saw with a thread in the cap of the hole saw. Hol”-18 thread drives hole saws 1-1/4″ and larger. The larger hole saws (1-1/4″ and larger) also have drive pin holes in the cap which receive drive pins from the arbor to facilitate quick and easy changes of the hole saw. Smaller hole saws connect to the arbor only with the thread and often get locked onto the arbor requiring tools to remove the hole saw.

 

There are quick-change systems in the market to help with quickly changing small hole saws on the arbor without the use of supplementary tools. The best sawing systems are universal. They will operate as a quick-change system with any brand of hole saw. Also, look for systems that don’t require the use of any proprietary components or adapters to operate. These adapters often lock onto the hole saw and may require the use of tools to remove the hole saw and may not deliver the tool-free changes you are looking for.

 

Pilot bits take most of the punishment in hole saw drilling. Many users drill with some oscillation movement to help clear chips from the cut. This puts a lot of side pressure on the pilot bit.

 

When drilling holes with a hole saw, you need a complete system designed to deliver the performance you need to do the job. This means all components of the system, not just the hole saw, need to provide you with durability and performance. When you choose the right system, you’ll find that cutting holes has never been easier.

 

If you need more information or choice of hole saws, welcome to check out K&W Tools Co., Ltd. – the company has specialized in kinds of metal cutting saws and woodworking saws for years. To get more details of metal hole saws, please do not hesitate to contact with K&W.

 

Article Source: https://www.grainger.com/content/supplylink-choosing-hole-saw

Understanding Hydraulic Pump Types and Differences

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There are many types of machinery that are driven by or actuated by a hydraulic pump. There are a variety of different systems that are used to generate the flow and pressure required and they all have a hydraulic fluid and a system that controls the fluid and pressure with hydraulic valves. The pump needs to drive and this can be done by any force generating device such as an electric motor, an internal combustion engine, wind power or even a person operating a lever or crank.

 

How It Works

A hydraulic fluid is put under pressure by the hydraulic pump and the pressure can then be used to drive a piston or drive unit via hydraulic lines. A hydraulic valve is used to switch the force on and off to give control of the device. The control can be mechanical or electrical and may be actuated manually through a lever or a button or automatically through control system.

 

Volume and Pressure

There are many different hydraulic systems and they all used a combination of volume displacement and pressure to work. The higher the pressure the more robust a system needs to be because of the tremendous forces involved. In general higher pressure systems are more efficient and the higher the pressure the less flow is required for the same application of force. There are two general types of pumps fixed displacement types that displace the same amount of fluid every cycle and adjustable displacement types that can vary the displacement for increased or decreased pressure.

 

Pump Types

There are many different types of hydraulic pumps that have different applications. Screw type pumps are good for high volumes at relatively low pressure. They are simple and effective but not particularly efficient. A gear pump has a more balanced pressure and flow and is very simple but is not very efficient particularly as pressure increases.

 

The vane pump is widely used in system of medium pressure up to 150 bar and beyond. While the axial piston pump is used in applications that require the highest efficiency. Where high pressure above 300 bars is needed the radial piston pump combine high pressure and low flow rates needed in these applications.

 

If you need more information of hydraulic pumps, please come and visit ANSON Hydraulics Industrial Ltd. – they are the professional manufacturer of various vane pumps. You can find variable vane pump, fixed displacement vane pump, hydraulic power pack unit, and much more hydraulic pumps there. To get more details, welcome to check out their website and feel free to contact with ANSON.

 

Article Source: http://peerlessengineering.com/understanding-hydraulic-pump-types-and-differences/

Mountain Bike Suspension Forks – A Buyer’s Guide

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Mountain bike suspension forks vary massively when it comes to travel, shock damping ability, stiffness and weight – and that’s before we even get onto price, which can run into hundreds or even thousands of pounds.

 

That means it’s important to know what to look for when buying a new fork.

 

What to Think About When Buying A Fork?

  • Travel

Mountain biking is a very diverse sport and there are suspension forks designed for every type of bike: cross-country bikes generally offer 80 to 120mm of suspension travel, trail bikes range from 120 to 140mm, enduro and all-mountain bikes have between 150 to 170mm, and gravity/downhill rigs go from 180 to 210mm.

 

The first question is how much travel will work best for you? All other things being equal, the further your fork can move, the more smoothly it can absorb impacts. But longer-legged forks have to be heavier to cope with the extra leverage and bigger impacts.

 

An extra 10mm of travel will tip head and seat angles back by roughly one degree, which makes steering slower and more stable. Running too long a fork can also overstress your frame and void the warranty, so always check what the recommended travel is for your bike before upgrading. In general, it’s best to replace your existing suspension fork with one with that offers a similar amount of suspension.

 

That said, many forks have travel-adjust features. These either let you drop the travel in small steps to tweak the bike’s geometry and handling to taste, or crush it down dramatically to give a shorter, stiffer fork.

 

  • Budget

The next question is budget. Sadly, there aren’t many budget forks that deliver a smooth suspension stroke and stiff, screw-through axle structure without weighing a ton. Damping circuits are also simpler on cheaper models, which mean less control in high impact or multiple-hit situations.

 

There’s a clear progression in standards of control and consistency up to around £400 / US$670, but after that the waters get a lot murkier and it’s time to be honest about yourself and your riding. The overall performance and reliability of basic forks has definitely improved though.

 

  • Control

The more travel you have, the harder it is to control – which makes damping control paramount. You should at least get adjustable rebound damping so the fork returns smoothly to its natural ride height, rather than bouncing back up with a clang. More advanced forks also have compression damping to help the spring slow down and absorb the impacts.

 

Top-end forks split compression damping into two separate circuits – low speed for controlling loads such as braking, cornering or movement under pedaling, or high speed for controlling sudden large loads such as square-edged rocks or landings. Having lots of damping adjustment is only useful if you know what you’re doing with it and have the time to tune it correctly though, so be honest rather than pretending that you’ll become a pro suspension fork tuner overnight.

 

If you’re likely to plug the fork in, do the minimum setup tweaking and then ride it day in, day out without servicing it then you’ll want a simple but totally reliable unit. If you clean and care as much as you ride, then you can get something a bit needier. If you’re a real fork fettler who’ll spend hours with a shock pump and a safe cracker’s level of dial turning dexterity to find your suspension sweet spot then it’s worth having a full range of adjustments to exploit.

 

  • Strength / Weight

As well as travel and tuning, you need to think about how much strength you really need, or you’ll just be carrying extra weight you’ll never use. Light, tight forks will suit climbers and other cross-country riders, while super-plush traction Hoovers are worth the extra weight for progressive envelope pushers. Getting the right balance is really important. Fork strength is hard to gauge though, so go by the manufacturer’s recommendations.

 

  • Compatibility

Most modern suspension forks use tapered steerer tubes which measure 1.5in at the crown and 1.125in at the stem.

 

There are also three different axle standards to consider: 9mm quick-releases can still be found on some lower end forks, though the majority of cross-country and trail forks now use 15mm thru-axles. Longer travel suspensions forks for enduro and downhill frequently use 20mm thru-axles.

 

If you have any interest in much more bicycle front forks, I recommend you to visit BEV International Corp. – they are the professional bike parts and accessories manufacturer in Taiwan. You can find kinds of bicycle frames, front forks, saddles, wheel sets there. To get more information of front fork series, welcome to check out their website and feel free to contact with BEV.

 

Article Source: https://www.bikeradar.com/gear/article/mountain-bike-suspension-forks-a-buyers-guide-55/

Do You Know What Narrow Fabrics Are?

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Have you ever heard about narrow fabrics? If your answer is NO, maybe you will wonder what exactly the term “narrow fabrics” includes. Here is a short explanation of the type of fabric:

 

By definition, narrow fabrics are “any non-elastic woven textile having a width of 12 inches or less and a woven selvage on either side.” They are small strips of fabric, often designed for a specific and practical purpose. Cords, braids, and lanyards are commonly used items that are also narrow fabrics. They are woven on special looms, including the recently developed quad axial loom which allows for the insertion of yarn from four directions and makes both a thinner and stronger product than the traditional layered strips joined with Z fibers were.

 

Narrow fabrics were initially used in the garment industry on hats, corsets, and lingerie and in military uniforms as well. Nowadays soldiers will also find narrow fabrics in their pack webbing and parachutes as well as their waist belts, helmets, and body armor.

 

If you pay attention to the everyday objects in your life, you will see lots of narrow fabrics, from the seat belts in your car, to the leash you walk your dog on, to the tough fabric edging on your mattress.

 

Recently, as technology has advanced, narrow fabrics have been used to make 3D medical devices such as the woven bifurcate that is used to treat aortic abdominal aneurysms. The strong fabric device is threaded into place to support the artery and reduce the aneurysm. Eventually, as the patient heals, this device will become a part of the artery itself.

 

During a procedure used to replace damaged heart valves, a narrow fabric medical device is used to fish out any surgical debris after the new valves are in place. The future promises more such medical technology. Other commonly known narrow fabrics used in the healthcare industry include rigid gauze, bandages, and fiberglass bands.

 

And, of course, narrow fabrics are used to join carpet seams during installation, whether inside the house or on the football field.

 

Narrow fabrics can be found almost anywhere and have a myriad of uses from every day to high tech. So the next time you take your dog for a walk or admire the carpet in your living room, remember narrow fabrics!

 

If you have any interest in narrow fabrics, come and visit Maw Chawg Enterprise Co., Ltd. – they are the professional yarn supply in Taiwan. You can find kinds of quality fabrics there. To get more details, welcome to check out their website and feel free to contact with Maw Chawg.

 

Article Source: https://www.bondproducts.com/narrow-fabrics/

Reducing Sinker and Wire EDM Consumable Costs

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A key area for improvement in EDM operations is the reduction of EDM consumables. New technologies, machine settings, and improved material grade limit ram or sinker EDM electrode wear to 0.1% while maintaining productive machining speeds. For wire EDM, new low-consumption technologies reduce the biggest expenses—the wire itself—by as much as 50 percent.

With all EDM machines, you experience the benefits of designing and cutting complex shapes and tapered holes with hard metals. You can depend that the machine has the capacity to cut exactly what you want. Sinker EDM machines use an electrode and workpiece submerged in liquids such as oil or dielectric water. A power supply is connected to the electrode and generates an electrical potential between both of the parts, producing a breakdown to form a plasma channel and spark jumps. The sparks initiated by the power supply often times strike one another.

In the sinker EDM process, wear on the electrode starts as soon as the erosion process begins. As metal is burned away on the workpiece, the electrode gradually experiences wear loses its fine details, and is dimensionally changed. Minimizing electrode wear is not only critical to reducing costs and lead times but also improving part accuracy.

From a general sinker EDM perspective, quality graphite electrode materials provide the most productive machining speed. The wear rate of a graphite electrode depends largely on the size of the detail, the electrode reduction amount, and the power settings used. However the grade of the graphite is a contributing factor. Using the correct grade of graphite will limit wear and rate of erosion.

Wire electrical discharge machining uses a single string of thin metal wire to cut thick metals for precise incisions and splits. Similar to Sinker EDM, Wire EDM uses an electrode and spark to cut metal. Using a spark erosion technique, Wire EDM machining submerges the part being cut in deionized water and the wire acts as the electrode, creating a spark that roughs or skims the part into the desired shape without the wire ever coming in contact with the part.

The price of a wire EDM machine is minimal when compared to the cost of the wire over the life expectancy of the machine. Excessive wire consumption on a wire electrical discharge machine is costly. Technology that allows slower unspooling speeds without compromising results appears to be the answer. The wire is the single highest expense in operating a wire EDM. With even the least expensive EDM wire running $5 to $6 per pound, investing in low-wire consumption EDM machines appears to be the answer.

A key area for improvement in EDM operations is the reduction of EDM consumables. For Sinker EDM users, consider using better grades of quality materials to reduce cost. For Wire EDM users, consider investing in new technology with machine settings that reduce the amount of wire used.

Article Source: https://graphel.com/blog/save-money-edm-sinker-consumable-costs/

Tips for Making Sheet-Metal Parts

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Follow these straightforward guidelines to create durable parts that exactly meet your design’s requirements.

 

In sheet-metal fabrication, parts are formed from metal sheets by punching, cutting, stamping, and bending. 3D CAD files are created using a host of different CAD packages and then converted into machine code, which controls machines that precisely cut and form the sheets into the final parts. Sheet-metal parts are known for their durability, which makes them great for a wide variety of applications. Parts for low-volume prototypes and high-volume production runs are most cost-effective due to large initial setup and material costs.

 

Below are some tips and guidelines for designing sheet-metal parts. If you follow the design advice and maintain the tolerances expressed in this article, you are more likely to end up with parts that meet the needs of your designs.

 

Wall Thickness

Parts should maintain a uniform wall thickness throughout their entirety, but this should be easy because parts are formed from a single sheet of metal.

 

Bends

Sheet-metal brakes bend sheets into a part’s desired geometry. Bends in the same plane should be designed in the same direction to avoid having to reorient the part during manufacturing, which will save money and time. Another trick is to keep the bend radius consistent to keep parts more cost-effective. Thick parts tend to become inaccurate, so they should be avoided if possible.

 

Rule of thumb: To prevent parts from fracturing or distorting, make sure to keep the inside bend radius at least equal to the sheet’s thickness.

 

Curls

Holes should be placed away from the curl at least a distance equal to the radius of the curl plus the material’s thickness. Bends should be at least six times the material’s thickness plus the radius of the curl.

 

Rule of thumb: Outside radius of curls must be at least twice the sheet’s thickness.

 

Countersinks

Countersinks must be separated from each other by a distance of at least 8 times the material thickness, from an edge by at least 4 times the material’s thickness, and from a bend by at least 3 times the material’s thickness.

 

Rule of thumb: The maximum depth for a countersink is 3.5 times the material’s thickness.

 

Hems

Hems are folds to the edge of a part that create rounded, safe edges. Hems may be open, flat, or tear-dropped, and tolerances depend on the hem’s radius, material thickness, and features near the hem. It should be noted that flat hems should be avoided because they risk fracturing the material at the bend.

 

Rule of thumb: For open hems, the inside diameter should at least equal to the material thickness (larger diameters tend to lose their circular shapes); and the return length should be at least 4 times the material’s thickness. Tear-dropped hems must maintain an inside diameter of at least equal to the material’s thickness, an opening of at least ¼ the material’s thickness, and the return length should also be at least 4 times the material’s thickness.

 

Holes and Slots

Holes and slots may become deformed if positioned near a bend. The minimum distance that holes should be placed from a bend is a function of the material thickness, bend radius, and the hole’s diameter. Holes should be at least 2.5 times the material thickness plus the bend radius away from any bends. Slots should be placed 4 times the material’s thickness plus the bend radius away from the bend.

 

Be sure to put holes and slots at least twice the material’s thickness from an edge to avoid a “bulging” effect. And holes should be separated from each other by at least 6 times the material’s thickness.

 

Rule of thumb: Keep hole and slot diameters at least as large as the material’s thickness. Higher-strength materials require larger diameters.

 

Notches and Tabs

Notches must be at least one-eighth of an inch (3.175 mm) away from each other. For bends, notches must be at least 3 times the material’s thickness plus the bend radius. Tabs must be at least 0.04 inches (1 mm) from one another or the material’s thickness, whichever is greater.

 

Rule of thumb: Notches must be at least 0.04 inches (1 mm) thick or as thick as the material, whichever is greater. A tab should not be any longer than 5 times its width. Tabs must be at least 0.126 inches (3.2 mm) thick, or two times the material’s thickness, whichever is greater. Tab length should be no larger than 5 times its width.

 

Corner Fillets and Relief Cuts

Sheet-metal parts may have sharp corners, but designing a fillet of ½ the material’s thickness will make parts more cost-effective.

 

Relief cuts help parts avoid “overhangs” and tearing at bends. Overhangs become more prominent for thicker parts with smaller bend radii, and may even be as large as one half of the material’s thickness. Bends made too close to an edge may cause tearing.

 

Rule of thumb: Relief cuts for bends must be at least one sheet’s thickness in width, and be longer than the bend radius.

 

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