Collision Avoidance or Detection? (Part 2)

May 16, 2012 By jjaje Leave a Comment

Automatic Avoidance is always better than detection.

In the last Blog Post, there was discussion about collision avoidance and detection, especially as automatic avoidance relates to 5-axis machining.

Today we will look at collision avoidance earlier in the process, during roughing.

Difference between Collision Detection and Avoidance.

Collision detection is when your CNC CAM software calculates a cutterpath, which often only takes the tool shape into account, but not the holder or the physical milling machine, then afterwards recheck it for and collisions. If there are any, then manual editing, or some other changes are required to remove the collisions yet still mill the entire part.

Collision Avoidance is when the collisions can be avoided in the first place, during the calculation of the CNC cutterpaths. When roughing, this may include the Tool and Tool Holder, and possibly the spindle.

Mill With the Shortest Tool Possible

You will that mantra from tool vendors all the time, when speaking about performance. Do as much milling with eh shortest tool as possible, and only use a longer tool where necessary, or utilize the short tool at different cutting angles if possible, to maximize performance.

Look at the picture below, in this case we can actually mill out 90% of the material with a very short cutter. We are using the strategy of roughing with a large cutter to take advantage of good material removal rates, and we will use a cutter with a Length/Diameter ratio of 0.9.

Part with tool and holder

Part with tool and holder

In this case, the holder is quite large, so although we can remove the majority of material with this short and sturdy cutter, there will be areas of additional stock to remove.

When you look at the cutterpath from the +Z direction, you can readily see that the CNC CAM  Software automatically limited the cutterpath, taking the tool and holder into consideration, to avoid all collisions, versus just finding collisions after the fact.

Stock Condition after +Z cutterpath

Stock Condition after +Z cutterpath

How the remaining material is removed can be done in multiple ways. Perhaps a different tool or holder from the +Z direction, or if you have the capability to rotate the part, either by a multi axis machine, or simply unbolting it and flipping it on the side, then you can continue to use the same short, sturdy tool to machine the part from other angles, as shown in the picture below.

Roughing with short tool in alternate directions

Roughing with short tool in alternate directions

Other Necessary CAM software Technology

To accomplish multi axis roughing, your CAM software must include the ability to work on a 3D stock model.

To accomplish automatic collision avoidance during roughing, as we did here, then your CAM software must also include the Dynamic Stock Model. Which is a topic for another blog :)

 

 

Filed Under: 5 axis cnc software, CADCAM, CAM software, CAM tips & tricks, NC machining, NC software

CNC – Collision avoidance or collision detection?

April 30, 2012 By cjordan Leave a Comment

For 5-axis applications not only does the CADCAM software have to consider actual collisions with the tool and the tool holder, but also the kinematics of the machine tool itself. For 3-axis machining the concern is mainly the tool length and holder ensuring that it can get into each part of the job without a collision.

For systems with just collision detection, the software tells the user that there is a problem and where the problem is, but the user then has to work out what needs to be done to get over the problem for himself. In some cases this can be very complex and requires detailed investigation of the surface topology of the part.

With CNC software such as WorkNC, users can generate the collided and uncollided toolpaths and get information about the minimum tool length required to finish the job. With this information engineers can cut as much of the part as possible with short rigid cutters and restrict to a minimum, machining with long tools. Best of all, the software does all the calculation for you, so that you can be sure of a reliable, safe and optimized result.

One of the benefits of 5-axis machining is being able to cut much more of the job in one setting with the shortest possible tools, minimizing resetting and secondary operations. If the CAM software just pinpoints where there is a problem, which it will do with collision detection, it is likely that the whole toolpath will need to be recalculated after the problem has been resolved. Producing a useable toolpath this way could take several attempts so at the very least it will be time consuming and tedious. With collision avoidance, the software goes a stage further as it anticipates potential problems as you are programming. Again giving the uncollided toolpath and inserting flip and unwind movements where the axis limits of the machine have been reached.

Having intelligence within the CAM software that provides a solution to potential problems as they occur has got to be a lot better than just letting the user know that a problem exists.

Antonius Köster, who uses WorkNC Auto 5 in Germany, gave this example of one of the problems resolved with collision avoidance. “For an aerospace supplier from the Black Forest, we machined a component which required the tool holder to move inside the part through a drilled hole so that we could mill a pocket at the bottom. Not only was the cutter moving inside the part, but the whole tool holder. This was a really challenging task.”

Filed Under: 5 axis cnc software, Aerospace, CADCAM, CAM software, CAM tips & tricks, NC machining, NC software Tagged With: , , , , , , , ,

Clouds and CAD CAM Software – Part 2

April 5, 2012 By jjaje 4 Comments

In Part 1, we examined what the “cloud” is, and one of its biggest uses, as cloud storage. This week we will examine Cloud Computing and how it relates to CAD & CAM software. First, let’s look at how things have come full circle.

Ye Olde Mainframe

While I may be dating myself with this statement, but one of the first CAD workstations I used was actually not really a workstation. It was a graphics terminal, hooked up to a mainframe computer. The actual computer was behind some locked doors in some windowless room, while CAD operators accessed the computer via a terminal. In this case, it was a graphics terminal, rather than a text only terminal, so that one could see the CAD graphics.

Calculations were not performed on the terminal, but rather on the mainframe in the other room. Data files were stored there too.

Typical manframe and graphics terminal

Mainframe and Graphics Terminal

Workstations Ahoy!

Eventually, workstations began to replace mainframes and graphics terminals. Dedicated Unix workstations could perform CAD CAM calculations faster, with greatly enhanced graphics capabilities, all for a lower overall cost. Graphics calculations as well as the necessary CAD and CAM calculations were all done locally, on the workstation’s CPU. Files may have been stored locally or on a file server elsewhere.

Eventually Windows PC based workstations became powerful enough in both CPU calculations and graphics capability to replace most Unix workstations in the CAD CAM fields.

Unix and PC based workstations

Unix and Windows PC based workstations

Cloud Computing

So then, cloud computing is kind of going back to the graphics terminal, centralized calculation model of the mainframe example above. Calculations are done on the computers in the cloud, files are stored in the cloud. Your computer acts as a graphics terminal to view and use the data. Often, your internet browser is used as the interface for your program running in the cloud.

For many applications, this model may work fine, but how well does it work for CAD and CAM today? To answer that question, let’s look to a popular cloud based graphics application, Google Earth. This is a wonderful product that is very fun to use. For a product like this, cloud usage for data makes perfect sense, as it would take too much storage space, approximately 70 terabytes,  to store all of the images for the whole planet that Google stores.

However, if you’ve used Google Earth, you’ve probably seen images like the one below: This is where the terminal, your computer, is waiting on data from the cloud, Google, before showing you the final image.

Blurry Google Earth waiting for more data

Blurry Google Earth waiting for more data

Imagine this happening with your large CAD part all the time. Waiting for the image to get clear. Now you understand why, for the time being at least, advanced CAD CAM products that are CPU and graphically intensive would not yet utilize cloud computing.

Even a medium sized (36 inches) but fairly complex mold like the one below can require over 3 gigabytes of data when you consider stock model conditions, dozens of cutterpaths, actual B-Rep data, tessellated data for display purposes, etc. Even with a very fast internet connection, there would be considerable delay if all of the computing and data information came from the cloud.

Medium sized mold

Medium sized mold

 

Today, it would be difficult to perform complex CAD and CAM on large parts via cloud computing. This is not to say that in the future, things won’t be different. The one thing we can rely on is change! What are some current uses of CAD CAM and the Cloud that you can think of? DO you see Cloud Computing becoming important in CAD CAM? Leave a comment below.

 

 

Filed Under: CADCAM, CAM software, CAM tips & tricks, Other productivity software

The importance of good CAM technical support

February 28, 2012 By cjordan Leave a Comment

Have you ever bought a piece of flat pack furniture and found that there are a few special screws missing? First, you ring up the store and if you are lucky they answer the phone. Next, you talk to someone who clearly knows nothing about furniture and is not really interested in your problem. Finally, you give up and go to the hardware store or rummage in the garage until you find something which will just about do the job!

Imagine if that was your CAM supplier and your machine was stopped and your customer was on the phone – I think I can safely say that this would be classified as a bad day at work and you would probably need a few beers to get over it!

So, getting good support for your CAM system has got to be pretty much top of the list. What you need is a company that is available when you need it, knows what they are talking about, understands your business and your machines and which is enthusiastic about providing a solution. Lots of tools are available now so that support engineers can operate your PC for you, enabling a solution to be achieved in a few minutes. Where this is not possible, you need the engineer to understand the software and the problem so that a viable workaround can be implemented. In most cases, time is of the essence, so this type of quick response can make all the difference.

For customers using the distribution channel for a CAM product rather than the software developer, the local dealer’s knowledge of the system and your application is paramount. Good CAM vendors will make sure that their dealer channel is properly trained, has fast access to extra help for the more difficult problems, and that it can talk knowledgably about local machining techniques in the customer’s own language.

The best CAM vendors will also involve customers in the development process, listen to their requirements and, either create a special application, help them to implement advanced features in the system, or add new functionality into the next software release. Perhaps furniture shops could learn a thing or two…..

Filed Under: CADCAM, CAM software, CAM tips & tricks, NC machining Tagged With: , , , , , ,

Training keeps up productivity

February 8, 2012 By cjordan 1 Comment

To get the best from your CAM system it pays to take the trouble to do the training courses. Some CAM systems are virtually automatic and intuitive, so the training requirement is quite low and users can start producing CNC programs very quickly and easily.

However, every system has its extras that take a little more effort, but which can make a big difference to productivity. Batch processing of programs overnight, setting up sets of standard machining strategies for different types of component, implementation of feature recognition, and analysis of the CAD data to find draft angles and the smallest radius are just a few of the features available in some CAM systems that can produce big benefits. Although not difficult to set up and use, these types of advanced features can be quickly learnt on a training course, saving hours of trial and error experimentation.

Most CAM systems are being continually developed (if yours isn’t you need to look for a new one!) so extra training in the new developments makes sure that your company is taking full advantage of the improvements, helping it to stay at the leading edge in its field. Furthermore, continuous training helps to build up a closer relationship with your CAM supplier, enabling it to develop solutions to your individual problems and to ensure that you are using the existing capabilities in the software to your best advantage.

Successful companies work in partnership with their customers and suppliers so that they can offer a superior service and product. Close collaboration on both sides significantly improves the performance of both parties. Taking advantage of continual training opportunities raises skill levels and productivity making it a very important part of the relationship.

So, when’s the last time you took update training for the CAM system you use?

Filed Under: 5 axis cnc software, CADCAM, CAM software, CAM tips & tricks, NC machining Tagged With: , , , , , ,

Get Connected – Stay Connected

February 8, 2012 By jjaje Leave a Comment

Information Age / Digital Age

The present day has been called many things, two come to mind immediately, The Information Age and The Digital Age. Through search engines like Google, Bing, Yahoo, AOL and others you can figuratively get information overload of whatever you search for.

The Information Age refers to the plethora of information available at your fingertips, literally, by using the fingertips to enter some key words into a search engine. Where people may have purchased reference manuals to repair things in the past, one can now find the information online. Where one would see just a few reviews when investigating the purchase of a product, now one can find thousands of reviews.

The Digital Age refers to the plethora of items available via digital means. Many electronics stores have eliminated or drastically reduced their music sales department, since so many people simply download songs they like online. Real Time Entertainment, with products like Netflix, is now the largest source of internet traffic, over file sharing, browsing and social media.

Social Media

On top of this, social media websites have completely changed how people communicate, share information or simply “keep up” with others. If all the people on Facebook were a country, it would be the third largest country based on population.

Get Connected

About this time, you may be wondering what all of this has to do with CAD CAM software. Get connected! There, simple isn’t it.

Recently we held seminars for WorkNC Version 21. During these seminars, we did an informal poll of how much people are connected to the software they use day in and day out. How they get information on training, tips or upcoming shows where they might be able to attend and ask a question.

As it turns out, based on our informal poll, CAM operators are not that connected. They aren’t connected via some social media, and as such, they miss out on important information. We like to point out, if you only visit a tech session or user group once a year, you are too far outside of the loop. It’s worse for those that don’t even do that.

Following are some links and ways you can stay connected to Sescoi and WorkNC. You don’t have to follow them all, but you will find it beneficial to follow a few…

If you use a software product as a large part of your work and career, definitely get connected in some way, so you can get the most out of it.

Filed Under: CAM tips & tricks Tagged With: , , , , , ,

Plunge Roughing – Part 2

December 14, 2011 By jjaje Leave a Comment

Previously, we discussed the use of Plunge roughing as an alternative roughing strategy, especially to utilize older or under-used milling machines. What I wanted to do with this entry is provide a few pointers on plunge roughing.

Plunge Roughing – not for all parts.

First, as with all cutterpath styles, you need to match the best cutterpath strategies with the part geometry. Some parts are better suited to a plunge roughing strategy than other parts.

First, consider the amount of material removal. Plunge Roughing works better if removing a larger percentage of material from the original stock, as opposed to a small amount of material. If you only need to remove a small amount of stock from a part, plunge roughing, on a global level, may not be the best choice.

Second, consider the part geometry. Plunge roughing in an automated fashion work best when removing a larger amount of material from larger areas. That is, if you have a whole lot of small pockets, then plunge roughing may not be the best choice. However when you have larger, open, areas for which to rough, it can work much better.

One particular example where Plunge Roughing can be ideal is in hydroform tooling. See the image below of an example of a good part for plunge roughing. There is a high percentage of material removal, compared to the original block of material, and it has larger open areas.

Plunge Roughing example

Plunge Roughing example

Utilizing Finer Control with Plunge Roughing

We saw in the previous post that sometimes the stock condition after roughing is “rougher” with a plunge roughing approach. While a global automatic approach may work in most instances, sometimes a person wants finer control. This may be around certain features in the design, or more often, to mill a larger channel into a part.

In this case, you may make drive curves to follow around particular features, or in a channel. This is shown in the picture below, where we utilize a curve to follow the feature more closely.

Plunge Rough around Feature

Plunge Rough around Feature

Dynamic Stock Model and Plunge Roughing

When Roughing it is important for the CAM software algorithm to know where the tool has been, and where there is stock remaining. This is done via a Dynamic Stock Model, allowing the CAM software to know the condition of the stock at every point in the cut.

This is critically important with Plunge Roughing, because after the plunge cutting motion, the tool steps away from the wall, and off the floor a little before retracting. This keeps the cutter inserts from rubbing along the wall on the way back up. If the CAM software does not know the stock at all times, then that step away can not be calculated safely, and if it were to step awaay into material, it could mean disastrous results for the cutter and spindle.

Plunge Rough Step Away

Plunge Rough Step Away

So in conclusion, plunge roughing works better on some parts than other parts. As always match the CAM milling strategy to the CAD design. Utilizing a Dynamic Stock Model is the only way to ensure the safest Plunge Roughing.

Filed Under: CAM software, CAM tips & tricks, NC machining, NC software

Plunge Roughing – Offers more than many think.

December 7, 2011 By jjaje 3 Comments

Utilize Older Milling Machines

In a previous blog named Concurrent Working Part 2, we explored some ways of doing tasks simultaneously within your shop. One suggestion is to utilize an older, less powerful, mill to do certain tasks, such as squaring off stock, while utilizing the newer, more advanced mills for the 3d Sculpted shape milling.

Another way to utilize older milling machines is to use them for some roughing tasks. While they may not be able to rough as fast or well utilizing the newest high speed tools and roughing strategies, they can often be very good at Plunge Roughing, also called High Volume Roughing within WorkNC.

Plunge Rough Cutterpath on Whole Part

Plunge Rough Cutterpath on Whole Part

Benefits of Plunge Roughing

There can be many benefits to utilizing a plunge roughing strategy, and some of them are:

  • High Metal Removal Rates. Plunge roughing can allow for metal removal rates competitive with newer high performance roughing cutters, running on a machine over a dozen years old.
  • Cutter forces are along the axis of the cutter instead of radially to the cutter.
  • Consistent chip loads because of the algorithms and cutting style.
  • Heat goes away with the chip. You can often place your hand on the material immediately after cutting and it is only warm, but not hot to the touch.

While Plunge roughing does have good metal removal rates, if you are cutting a part with a lot of shape, the condition of the stock will be “rougher” after plunge rouging, with more material to re-rough than other roughing methods. While many may consider this a negative, if one already had to run a re-rough cutterpath regardless, you might as well run one where the tool is engaged in more material. As many roughing tools are designed to remove a larger width of stock, and often have premature failure when the width of stock is consistently narrow.

Result from Plunge Roughing

Result from Plunge Roughing

Have you tried Plunge Roughing? If so, tell us about your experiences int he comments.

 

 

Filed Under: CAM software, CAM tips & tricks, NC machining

Concurrent Working – Part 2

November 23, 2011 By jjaje 1 Comment

Previously we discussed concurrent working, or multitasking in a sense, to discuss how some tasks can be done in parallel. There are many ways for working in parallel that can help your shop to improve. Following are some ideas, and what we would like is for you to comment your own ideas.

Program CAM software cutterpaths on the shop floor, while the machine is running

With advanced CAM software, one programmer can program the next job(s) while their mill is running the current job. If you have confidence in the reliability in your CAM software, where one does not need to “babysit” the mill continuously, they can spend time while the mill is cutting, to get the next part programmed.

Run multiple mills with Advanced CAM software and a little planning

With Advanced CAM software, you most likely can have one mill operator / programmer run multiple mills. If doing parts with complex 3D shapes, that require roughing, semi finishing and finishing, it’s not uncommon for a person to run two or even more mills all simultaneously. This can be accomplished by prudent use of standard sequences (templates) and batch processing. Allowing the mill operator to set up the next mill, while one mill is running and his computer is calculating cutterpaths on the next model.

Utilize older machines

Many shops, as they buy new equipment, start to phase out or stop using some older equipment. Keeping an older machine busy, can help bottlenecks from forming on newer machines (Read the One Minute Manager by Ken Blanchard). Some ways to do this are by using an older mill to square up material to e moved to newer mills.

Another way is to mill differently on an older mill. Perhaps use an older mill to plunge rough a part, then semi finish and finish it on a newer mill. We discussed this topic in our regular Tip of the Week.

Cut multiple parts simultaneously

When milling smaller details, mounting several into the machine at one time, and milling them all at once, can be a time saver. Utilities such as WorkNC’s MPM, Multi Part Machining, help to automate this task allowing for optimized sorting of tooling.

While one group of parts is being milled, the others can be mounted onto a quick change pallet to be ready for when the machine is available.

What are your ideas?

This was just a few commonsense ideas. We know many of the readers have ideas of their own. We’d love to see them in the comments.

 

 

Filed Under: CADCAM, CAM tips & tricks

Working with lots of different CAD systems

November 18, 2011 By cjordan 1 Comment

Working with lots of different CAD systems – for subcontractors and suppliers this can be a real headache and especially if you are working with automotive or aerospace customers that use some of the high-end CAD packages.

In some cases there is no alternative to actually installing one of these CAD systems and employing a very expensive design engineer to run it, which can be justified if the majority your work is in the one market sector and you have to actively participate in the customer’s design process.

Thankfully for most people, CAD translation has moved on enough to make this unnecessary. For CAM systems neutral formats such as IGES and STEP or direct translators for products like CATIA, SolidWorks and Inventor are very reliable, enabling manufacturers to accept data from many different sources without a problem.

Once you have accepted that translators are OK, you can then choose the best CAM system for your application. Even if you have had to install the high-end CAD, transfer of model data is generally one way into the CAM system, so even for these applications a specialist, best of breed, CAM package will provide the best solution, reducing cycle times, improving quality and reducing tool breakage – real tangible savings.

Filed Under: Aerospace, Automotive, CADCAM, CAM software, CAM tips & tricks, NC machining, NC software, Other productivity software Tagged With: , , , , , , , , , , , , , , , , , , , ,
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