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What’s New inCimatronE 10

High Speed &

High Performance Machining

A Tour of High Speed Roughing and Finishing from a CAM Perspective

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High Speed Machining

Outline

High Speed Machining enables manufacturers to shorten machining times and to achieve a higher surface quality. This booklet explains the role of CAM software in High Speed Machining in the most straight forward way possible, in order to clarify the subject for experts and beginners alike. The publication was produced by CimatronE and has an agenda; in explaining the challenges and demands of CAM software during High Speed Machining, the booklet also aims to show that CimatronE offers an effective response to all High Speed Machining challenges and has the ability to leverage High Speed Machining, to make the most of its benefits. The booklet is divided into two sections, High Speed Roughing and High Speed Finishing. Each section includes a general outline of applicable High Speed Machining methods, an explanation of how NC programming differs from traditional machining, and, a concise review of CimatronE’s strategies, addressing the following questions:

• What is the difference between High Speed Milling (HSM) and High Performance Machining (HPM)?

• What should a CAM system provide to facilitate effective High Speed Machining?

• How are High Speed Machining strategies different from traditional machining strategies?

• How do I choose the right High Speed Machining strategy?

• How does my choice of strategy affect surface quality and machining time?

HOW DO MACHINING STRATEGIES AND TECHNIQUES VARY AS I PROGRESS FROM THE FIRST ROUGH THROUGH TO THE LAST FINISH OPERATION?

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CONTENTS

Section 1: High Speed Roughing ................................................................... 4

HPM or HSM? .................................................................................................................................. 4

Part I: High Performance Machining (HPM) .................................................................................... 7

HPM Enablers ........................................................................................................................ 7

HPM Machining Strategies .................................................................................................... 9

5-Axis Positioning ................................................................................................................ 12

Part II: High Speed Milling (HSM) .................................................................................................. 13

HSM Enablers ...................................................................................................................... 13

HSM Machining Strategies .................................................................................................. 14

Advanced Roughing Techniques ......................................................................................... 15

5-Axis Positioning ................................................................................................................ 15

Summary of High Speed Roughing ................................................................................................ 16

Section 2: High Speed Finishing ................................................................. 17

The High Speed Milling Concept ................................................................................................... 17

HSM Enablers ...................................................................................................................... 18

HSM Machining Strategies .................................................................................................. 19

Summary of High Speed Finishing ................................................................................................. 24

Conclusion ..................................................................................................................................... 25

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High Speed Roughing

High Speed Milling and High Performance Machining During the Roughing Process

INTRODUCTION

Among the priorities of manufacturers, in their attempt to be more competitive and better serve their customers, is the need to shorten delivery times. Manufacturers strive to do things faster at every stage of the process, attempting to cut design, programming and machining times. Two machining methods, High Speed Milling (HSM) and High Performance Machining (HPM), have become increasingly popular because of their ability to drastically speed up machining, while achieving better results.

HSM and HPM are facilitated by specially made tools, holders and machines, as well as a CAM system capable of creating effective HSM/HPM toolpaths.

This section of the booklet, which is intended for all manufacturing professionals, will explain how HSM and HPM are implemented during roughing (from the first rough to pre-finish), by addressing the central questions of the NC programmer: How can HSM/HPM be effectively implemented? When should HPM be used? and when should HSM be used? What are the strategy choices available for HSM/HPM? How does one choose which specific machining strategy to use? And what must a CAM system provide to facilitate effective HSM/HPM?

In answering these questions, this section also explains how CimatronE is designed to provide optimal results during high speed roughing.

HPM OR HSM?

Below is a diagram illustrating the difference between HPM and HSM. HPM (orange) involves either a large sidestep (1), a large downstep (2) or both at the same time (3). HSM involves a small sidestep and a small downstep (4).

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High speed roughing can be achieved using either of the two methods; when should each method be used?

The HPM method, which allows cutting with large sidesteps and downsteps at fast feeds, is the ideal way to maximize material removal. The manufacturer will prefer HPM for all of the first roughing operations, for which fast material removal is the foremost goal.

The roughing process, which includes all of the pre-finish operations, is also responsible for leaving behind a uniform remaining stock. This is where the more controlled HSM method comes in, as HPM would leave marks and scallops.

The two roughing goals, Fast Material Removal and Uniform Remaining Stock, and their changing priorities throughout the roughing process are illustrated below.

1 2 3

4

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Combining the two methods (HPM and HSM) can complete the roughing process in a significantly shorter machining time than that of traditional machining. This, of course, will only work if HPM and HSM are properly implemented and if cutting strategies are always appropriate to the geometry being cut.

Part I of this paper will cover the HPM method, the requirements for its effective implementation, and the way that CimatronE fulfills the role of a CAM system that both produces an effective rough and is adapted to the requirements of HPM. Part II will explore HSM for roughing along the same lines.

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PART I: HIGH PERFORMANCE MACHINING (HPM)

HPM fulfills its goal of faster material removal by working with either a large sidestep, a large downstep, or both simultaneously, and achieving as fast a feed as possible. During HPM with a large sidestep, the tool will be cutting at sidesteps that are 60-80% of its radius, which means that a 50mm cutter will be working with a side step of 30-40mm.

Enabling this level of sidestep has a huge pay off for the material removal rate, but can only work if the tools, holders and machines are built to withstand strong machining forces, and if the CAM software can create special toolpaths that minimize the strain. Below is a description of how this is done in CimatronE, followed by a concise review of strategies available in HPM, and how they are optimized.

HPM Enablers

Damage to machining equipment can occur as a result of sudden changes in the strain on the tool. In order to build a toolpath that enables use of the HPM method by reducing the strain on machine and the tool, a CAM software must eliminate drastic variations in machining direction and drastic variations in chipload, as well as ensure a constant removal rate (MMR).

In CimatronE, this kind of toolpath is achieved by including one or more of these 6 Enablers in traditional machining strategies:

1. All Rounds – Sharp corners can create a drastic change in the chipload, which could put a serious and dangerous strain on the tool and machine. CimatronE automatically rounds all corners to ensure that inevitable changes in the chipload are smooth and gradual, minimizing drastic impacts and reducing jerks.

2. Clean Between Passes – Complex geometries inevitably result in variations in sidestep. To ensure that this does not result in unmachined areas, the system automatically adds extra rounded passes.

3. Trochoidal Machining – When working with a small sidestep, an all rounded toolpath can create unwanted ridges. In this case, the system uses trochoidal machining to remove ridges. Trochoidal Machining can also be implemented to open slots.

4. Multiple Downstep – When slotting cannot be replaced by trochoidal machining, the system can automatically add several passes in the slotted area to achieve a smaller downstep, reducing the strain on the tool.

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The tool path above has been produced for a large sidestep and downstep, without the use of enablers.

The toolpath above demonstrates the All Rounds Enabler (1) for large sidesteps and downsteps

The above toolpaths were produced for a large downstep and a small sidestep. The toolpath on the left is properly rounded for HPM but requires the additional Trochoidal Enabler (3) to ensure that no ridges are left behind.

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5. Stretched Rounds – Working with a rounded toolpath combined with large sidesteps can leave unwanted ridges in corners. The system smoothly stretches the pass in corners, eliminating ridges.

The above toolpath features a large sidestep and includes the Clean Between Passes Enabler (2) and the Stretched Round Enabler (5)

6. Feedrate Adaption – The system does all it can to create a toolpath trajectory that provides as constant a chipload as possible. Additionally, the system can automatically increase and decrease the feed rates, as necessary, to maintain a constant chipload and MRR.

One of the ways in which CimatronE ensures these Enablers are incorporated everywhere they are required, is by working with a High Accuracy Stock, which allows the system to spot problematic areas and automatically apply the relevant Enabler. High Accuracy Stock also ensures maximum productivity by eliminating unnecessary air cutting.

HPM MACHINING STRATEGIES

HPM roughing, for the most part, involves use of traditional Z-layers machining that incorporates HPM Enablers. The first section below will explain in brief how Z-layers machining works and what different machining strategies are available within this type of machining.

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The second section, about large downstep HPM Optimization, describes two options that significantly speed up the roughing process when working with a large downstep.

Lastly, there is a section on plunge roughing, which is also a form of HPM, but it works differently, with special tools that require a special toolpath.

Z-Layers Machining

Z-Layer machining works by dividing the stock on the vertical axis into horizontal layers and machining by layer. There are two types of Z-layer machining strategies, Spiral strategies and Parallel strategies. CimatronE also offers considerable optimization for spiral strategies.

Spiral Strategies

Within the context of Z-Layers machining, the main roughing strategies are the Spiral strategies, including Stock Spiral, Spiral (Out - In) and Spiral (In - Out). The user can program machining using any one of these strategies, or work with full optimization; CimatronE can combine all of the spiral strategies, assigning the optimal cutting strategy to each area of the part, based on the shape of the part and the stock.

Spiral (In - Out) is most suited to machining cavities because it cuts within a machining boundary from the inside out, and thus avoids slotting near the surface of the part. Stock Spiral is used for most cores because it cuts along offsets of the part, approaching from the open area outside the stock. It is in effect a type of profile cutting. When the system recognizes that Stock Spiral will result in an excessive number of air motions, it can switch to the Spiral (Out - In) strategy, which cuts within a machining boundary from the outside in.

Parallel Strategies

Parallel Strategies are fully available for HPM including Uni-Directional Parallel and Bi-Directional Parallel, which move the toolpath along straight lines with a constant distance between passes. Parallel strategies are effective for the machining of wide areas where machining boundaries are either straight or open.

From left to right: Parallel Strategy (Bi-Directional), Stock Spiral, and Spiral (In - Out)

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Large Downstep HPM Optimization

The following two timesavers actually add passes into the current operation to shorten the machining time of future operations, effectively shortening the entire machining process.

Between Layers inserts passes with a small down step into a large downstep operation, allowing for a smoother result and a more uniform remaining stock. This hybrid machining, in which HPM is combined with small downstep machining, can save considerable amount of time by eliminating the need for extra pre finish operations.

Hit Planes adds a horizontal plane of machining at the horizontal planar surface of the part. This means that the final uniform result can be achieved in the first rough for some geometries. This option can also be used when working with smaller downsteps.

Large Downstep HPM Optimization: The primary machining strategy is a stock spiral strategy with a large downstep (blue), this is completed first. A single Z-layer is shown. Then the between layers passes (black) shave off remaining stock above the last layer of machining. Finally, the hit planes passes (turquoise) achieve a uniform remaining stock on the horizontal planes.

Plunge Roughing

Plunge Roughing takes place as the major roughing operation in an area that is narrow and deep. Although Plunge Roughing does not require use of the HPM Enablers mentioned earlier, it is still considered HPM because of its significant removal rate. Plunge Roughing requires a specific toolpath, relevant not only to plunge milling itself but also to the specific tool that is being used. Plunge milling can take place with a centered tool, which works like a drill, or with a non centered tool, and in this case additional optimization is required—all of which is available in CimatronE.

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5-Axis Positioning

With 5-Axis positioning, the manufacturer can significantly improve any of the strategies described above, by allowing the use of shorter, more robust tools, thus shortening machining time.

In order to get the maximum productivity for 5 Axis positioning, the CAM system must use a multidirectional stock, which is automatically updated throughout the process to ensure maximum efficiency within a safe process.

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PART II: HIGH SPEED MILLING (HSM)

HSM is the second of two high speed roughing methods. While HPM helps increase the material removal rate by facilitating larger downsteps and/or sidesteps, HSM provides a solution for faster machining when using a small sidestep and a small downstep, combined with very high spindle speed and feed rate.

Usually, a small sidestep and downstep become necessary in the second stage of the process, where the main goal is to achieve a uniform remaining stock across the entire surface of the part. However, there are situations in which a small sidestep and downstep are used for the entire roughing process, for example when working with small parts.

As with HPM, HSM requires several different components in order to effectively speed up the roughing process. We will briefly discuss the family of components that are necessary for HSM. Then, we will focus on CAM software, by looking at how CimatronE provides the strategies and techniques necessary to perform HSM at different stages of the roughing process and on parts with different topologies and shapes.

HSM Enablers

An HSM toolpath is one that reaches and maintains very high spindle speeds and feed rates, with a trajectory that is smooth and rounded throughout, no matter what the topology or geometry of the part.

CimatronE utilizes four Enablers that can turn any traditional toolpath into a fully optimized HSM toolpath (illustrated examples of these enablers can be found in the finish section, on page 18).

1. All Rounds – When cutting at high feed rates, there can be no sharp corners in any of the passes, as this would cause machine jerks and damage the tool and the machine. It could also result in variations in tool load. During calculation of the toolpath, the system automatically rounds all passes where necessary.

2. Clean Between Passes — This is to prevent large scallops no matter what the complexity of the geometry. The system automatically adds extra passes where there are variations in sidestep.

3. Tangential Approach/Retract – When machining at high speeds, the approach to the part and the retract must be rounded and tangential to guarantee a smooth engagement.

4. Trochoidal Machining – This removes large ridges resulting from rounding sharp internal corners.

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HSM Machining Strategies

The optimal strategy for HSM roughing varies considerably based on the topology and the shape of the part being cut, and based on the current stage of the roughing process and its associated aims. Thus, a CAM software must offer the same flexibility in HSM that it offers during the traditional roughing process.

CimatronE offers its Z-Layer Optimized roughing capabilities, with full HSM compatibility. In addition to this, it also offers a Flowline strategy, which allows for the roughing of complex freeform parts.

There are also two additional techniques which utilize the above strategies. These techniques are Rough and Finish (which combines both rough and finish in the same operation) and Micro-milling (for use with very small tools).

Z-Layers

Z-Layers works by dividing the stock on the vertical axis into horizontal layers and machining by layer. CimatronE can automatically choose the right cutting strategy based on the shape of the part. Z-Layers machining can be adapted to HSM machining along with its Single Operation and Full Process Timesavers. For a full account of Z-Layers machining, including information on spiral and parallel strategies see HPM strategies (pages 10-11).

Due to small downsteps and sidesteps, machining using HSM can lead to huge toolpaths, especially when working with larger parts. CimatronE can effectively handle these types of toolpaths for any part and adapt them for HSM machining.

Flowline Roughing

Flowline Roughing follows the natural form of the part, covering the entire machined area in an uninterrupted tool motion to minimize air-cutting and leave a smooth, uniform remaining stock. The system facilitates smooth cutting by ensuring that machining does not exceed the maximum sidestep, even when the topology of the part makes variations in downstep or sidestep inevitable.

This form of roughing involves 5-Axis Simultaneous Milling, for parts whose geometry is difficult to machine and those requiring a process that is more responsive to shape and topology. These mainly consist of parts for the aerospace industry, like impellors (for which CimatronE provides a dedicated roughing application). This kind of roughing is unfeasible without HSM because of the very long toolpath that would take too long to machine at regular feeds.

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Advanced Roughing Techniques

Mixed Rough and Finish and Micro-milling are highly optimized operations that allow effective work on parts with specific topologies. Both can use either of the two strategies mentioned above, and continue to be extremely effective under HSM conditions.

Mixed Rough and Finish (in the Same Operation)

Mixed Rough and Finish is especially useful in situations where the part includes high narrow walls, which are often found in electrodes and in aerospace parts, like blades. Mixed Rough and Finish works layer by layer, cutting with a roughing downstep with a given offset, and then switching to a finish downstep on the surface of the part.

Micro-milling

Micro-milling enables efficient roughing of small parts using very small tools and working at very tight tolerances, in order to achieve an extremely high level of accuracy. Performing this kind of machining at HSM speeds, with cutters that have diameters as small as 0.2mm, can only be done with a completely rounded toolpath. This type of machining also requires a very accurate stock, so that the system can calculate the optimal toolpath and machine safely, while avoiding air cutting.

5-Axis Positioning

5-Axis Positioning can significantly increase productivity by cutting the part from a set of optimal angles, using shorter, robust tools. As in Micro-milling, a very accurate stock allows the system to calculate the optimal toolpath and machine safely, while avoiding air cutting.

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SUMMARY

As part of a continuing effort to shorten machining times during the roughing process, manufactures have adopted two methods, High Performance Machining (HPM) and High Speed Milling (HSM).

HPM and HSM complement each other to enable efficient high speed roughing in any situation, provided that the right tools, holders, machines and CAM software are used. HPM is extremely effective for fast material removal, especially useful for the initial process stages, whereas HSM speeds up machining where more controlled cutting is desired, especially when trying to achieve a uniform remaining stock.

The CAM system must create the conditions necessary for effective HSM and HPM by producing a toolpath that is compatible with High Speed Machining. It must provide the appropriate strategies that will allow optimal cutting of any topology. CimatronE does this by allowing the NC programmer to augment any traditional roughing strategy so that both the strategy itself, and its optimizers and timesavers, work with the HSM/HPM methods.

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High Speed Finishing

High Speed Milling During the Finishing Process

INTRODUCTION

High Speed Milling (HSM) has become increasingly popular because it offers a competitive edge to manufacturers by simultaneously shortening machining times and enabling a better surface quality. HSM is a blend of several different components – machines, cutters, holders, controllers, and CAM software -- all of which have to be suited to this type of cutting.

This paper will explore the use of HSM for finishing, with an emphasis on surface quality, from the CAM software perspective. CAM software needs to optimize the toolpath so that it will perform HSM effectively; the software should also provide the user with a flexible choice of machining strategies so as to produce very high surface quality no matter what the topology of the part.

THE HIGH SPEED MILLING CONCEPT

Faster machining can allow manufacturers to shorten machining times. It can also make it feasible for manufacturers to use long finishing toolpaths, with small scallops, which would otherwise make machining times too long. Thus the goal of the HSM concept is both to allow manufacturers to shorten machining times and increase surface quality.

In order for HSM to take place effectively, it requires specialized machining components (like machines, tools, holders, and controllers) that can handle extremely fast feeds and spindle speeds. Additionally, the CAM software needs to create a toolpath that both results in fast machining and protects the other machining components. In order to explain how a CAM system can do this effectively, we will focus in on the CimatronE CAM system.

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HSM Enablers

An HSM toolpath is one that reaches and maintains very high spindle speeds and feed rates, with a trajectory that is smooth and rounded throughout, no matter what the topology of the part. CimatronE utilizes four Enablers that can turn any traditional toolpath into a fully optimized HSM toolpath.

1. All Rounds – When cutting at high feed rates, there can be no sharp corners in any of the passes, as this will cause machine jerks which will leave marks on the part itself and damage the tool and the machine. During calculation of the toolpath, the system automatically rounds all passes where necessary.

2. Clean Between Passes — This is to ensure that a constant sidestep and uniform scallops are maintained no matter what the complexity of the geometry. The system automatically adds extra passes where there are variations in sidestep.

3. Tangential Approach/Retract – When machining at high speeds, the approach to the part and the retract must be rounded and tangential to guarantee a smooth engagement.

4. Trochoidal Machining – This removes large ridges resulting from rounding sharp internal corners. While trochoidal roughing is a standard part of HSM roughing, trochoidal finishing is often problematic because it can cause witness marks. CimatronE’s Zero Overlap Trochoidal cutting uses an advanced algorithm to bypass this problem and produce a truly smooth surface finish.

The HSM Enablers will be demonstrated on the section of this part that is in the small square.

Traditional Toolpath: This toolpath has not been optimized for HSM and, as a result, has sharp corners.

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All Rounds only: The toolpath above is using the “all

rounds” enabler only, this causes significant variations in sidestep.

The above tool path includes All Rounds, Clean Between Passes (white) and Trochoidal Machining (Yellow).

HSM Machining Strategies

In any situation, achieving the best possible surface quality means keeping scallop size as small as possible, achieving a small radial cutting width (ae) and starting the finish operation with a uniform remaining stock. Surface quality can also be improved by having as few tool lifts as possible, few tool changes and a minimum amount of machine vibrations. Additionally and very importantly, the finish strategy has to be adapted to the surface topology. All these factors are as true for HSM finishing as they are for traditional finishing.

In order to provide the flexibility to perform High Speed Milling effectively on any topology, CimatronE takes four main types of finishing strategies and optimizes them to work at very high speeds, by incorporating the HSM Enablers.

In addition, CimatronE offers further flexibility by providing a powerful Remachine capability which is designed for finishing of corners with small radiuses. The four types of strategies, as well as Remachine, can be further optimized to the topology by getting the system to match the right strategy to the right geometry or by using 5-Axis technology. All of these additional methods work effectively and safely when performing HSM.

We will discuss HSM finishing strategies in three parts by looking first at the four types of finish strategies, then at Remachine and lastly focusing on Strategy Optimization.

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1. The Four Types of Finish Strategies for HSM

The following are four different types of finishing operations. These ‘types’ are in essence a full category from which many different strategies can be derived depending on the parameters. CimatronE can generate an HSM toolpath for every type of strategy.

The first type of strategy is a Parallel strategy in which the toolpath moves along straight lines with a constant distance between passes. This strategy is mostly effective for geometries that are shallow or flat across the path direction, because a slope across the passes would result in an uneven sidestep as measured on the surface of the part.

The second type of strategy is a Z-layers strategy which divides the geometry along the Z axis producing a toolpath that cuts according to the geometry, at a certain height. This strategy is particularly useful for the machining of steep walls.

The orange surface of this object will be machined with a rouded parallel strategy, while the green walls will be machined with a rounded Z-layers strategy.

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The third type of strategy is a Spiral strategy. In this strategy there is a constant sidestep between the passes which are enclosed by one or more contours. This means that the strategy can be applied to a wide range of geometries and shapes, producing a smooth surface quality.

The fourth type of strategy is a Morphing strategy. This strategy ensures a constant number of passes between one contour and another. This means that the passes are very responsive to the geometry of the contours, and flow with the natural geometry of the surfaces; it can however result in major variations in sidestep, depending on geometry.

Connections

In any of the four types of strategies, there are two ways in which the tool can move from one pass to another: through the air or on the surface of the part. Whichever way is chosen, the motion from one pass to another must be rounded to accommodate high speed milling. If the tool remains on the surface of the part, CimatronE offers S-connections, which connect one pass to another in a rounded tangential S-shaped motion. A special True Spiral machining capability can create the entire toolpath as one helical spiral.

2D or 3D Stepover

While the first two types of strategies (Parallel and Z-layers) measure stepover on a horizontal or vertical plain only (potentially resulting in large scallops if the part surface slope changes dramatically), the Spiral strategy can measure stepover on the 3D surface of the part. This results in a uniform scallop size, even where there are drastic changes in the slope of the surface.

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One electrode, three HSM strategies: CimatronE’s total flexibility in High Speed Milling allows users to pick the strategy that fits the topology they are cutting. In this case, HSM Helical (true spiral) Z layers (right) provides a superior surface finish to HSM Z-layers (left) or morphing (center).

2. Remachine

Remachine is a highly optimized method of automatically removing material from a part that was left over by a previous cutter. Remachine includes reroughing, to ensure uniform stock width for the finish passes, and finishing, to achieve an optimal surface quality in just one operation. Because Remachine can optimize several of the different types of finish operations mentioned above, it is extremely flexible. An example of this flexibility is Remachine All Along, which creates a toolpath that works along the natural flow of the material that has to be removed. The Dilute option allows the user to skip passes in narrow areas where they are not necessary, saving machining time. The user can turn this option off (No-Dilute) to produce a super finish surface quality with no tool lifts.

The diagram above shows an example of Remachine, in which material left over by a previous cutter is removed by

the current cutter.

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3. Strategy Optimization: Vertical/Horizontal, Multi-cutter and 5-Axis Machining

Vertical/Horizontal, Multi-cutter and 5-Axis Machining further enhance the strategies mentioned above, allowing these strategies to be used in the most efficient way possible.

Vertical/Horizontal automatically combines two different strategies, by applying one machining strategy to steep areas and another strategy to areas with a gentle incline. The user simply specifies the boundary slope angle and the two strategies that should be used.

Multi-cutter chooses the optimal cutter in a situation where the geometry requires the use of a very long cutter during some of, but not all of, the finish operation. Multi-cutter will consider two or more similar cutters with different lengths and holders, using the shorter, more efficient cutters wherever possible, and using longer cutters only where they are absolutely necessary. Machining conditions, such as feed rate, are controlled per individual tool, to accommodate for the different tool lengths.

5-Axis Positioning can significantly increase productivity and surface quality by cutting the part from the optimal angle using shorter tools. In many situations this may mean that an area that would have needed Vertical/Horizontal or Multi-cutter optimization can be completed using one simple strategy.

5-Axis Tilting is an option that uses simultaneous 5-Axis milling to allow the tool to reach all required areas while avoiding collisions between the part and the shank or holder. Thus short robust tools can be used, with no or fewer tool lifts throughout the part. While simultaneous milling of freeform parts can be very complicated and time consuming, CimatronE’s Tilting is very simple to program; there is no need to define guiding contours.

The Multi Cutter optimizer means that a short tool can be used for most of the part (dark blue), medium tools will be used for some of the part (light blue and orange), and a long tool will only be used when absolutely necessary (green).

Using 5-Axis Positioning (center) and 5-Axis Tilting (right) means that short, robust tools can be used for all machining of this part. The direction from which milling occurs in the positioning example allows the finish operation to be performed with one short tool. In the Tilting example, an even shorter tool can be used.

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SUMMARY

When implemented optimally, HSM significantly speeds up machining, allowing manufactures to both reduce machining times and take advantage of the speed to produce longer toolpaths that offer a better surface quality.

CimatronE provides manufactures with the necessary flexibility when programming HSM. This means that NC programmers can work with any of the machining strategies and methods that CimatronE offers during traditional machining. The system can simply optimize each toolpath so that it allows the machine to reach and maintain high spindle speeds and feed rates, while cutting the part with a high surface quality.

CimatronE provides full HSM optimization for finish operations. In this paper, we have seen that the flexibility to choose the right HSM finishing strategy for a part allows NC programmers to achieve the highest levels of surface quality at high speeds.

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CONCLUSION

In continuing attempts to shorten overall delivery times by reducing machining times, manufacturers have turned to High Speed and High Performance Machining.

High Speed Milling (HSM) and High Performance Machining (HPM have the potential to greatly speed up machining and to improve overall results, ultimately achieving a fast rough and an efficient finish with a superior surface quality.

In Rough, HPM and HSM can be combined within the roughing process, where the focus gradually changes from fast material removal (HPM) to uniform remaining stock (HSM). In Finish, HSM is applied to achieve both faster machining and higher surface quality.

Successful implementation of High Speed Machining involves using cutters, holders, spindles, controllers and CAM software that is adapted to work at high speeds. If any of these components are not optimally adapted, results will fall short of expectations.

For the CAM system to be effective, it has to go beyond superficial “compatibility” with High Speed Machining methods, empowering the manufacturer to create a process that is as fast as it can possibly be, and is also controlled enough to achieve a uniform remaining stock and ultimately a high quality finish.

CimatronE achieves this by allowing the NC programmer to use all of the strategies available in traditional machining, providing the flexibility to match every topology with the right strategy. The strategies are optimized to work under HSM and HPM conditions so that the manufacturer can enjoy the full benefits of High Speed Machining.