CNC Machining Blog - Tips and Tricks for Machinists

As machinists we apply our skill, knowledge and experience to produce the best looking and most accurate parts that we can. We take a great deal of pride in the products that we produce, and we want others to see that pride in the finished product. But what do we do when we aren’t getting the results that we want? When dimensionally the parts meet blueprint specifications, but the surface finish and overall appearance is less than desirable? When this happens we need to go back the basics and ensure that we are using the best machining practices that we know to be correct.

In the last article we discussed the questions that you should be asking yourself when buying a CNC lathe, and we discussed some of the common terminology associated with CNC turning. In this article I would like to build on the topic of purchasing considerations, and want to discuss the ins and outs of the two main bed designs – the true slant bed and the flatbed “flying wedge” configurations.

When purchasing a CNC lathe, there are several questions that you need to ask yourself before you begin the process. Some of these questions will be quite obvious: How much axis travel do I need? What size chuck should I look for? How many tool stations are on the turret? What is the spindle bore size? Etc... However, there are other specifications that are just as important, but not always so obvious: What is the maximum swing distance that my work will require? What is the maximum turning diameter necessary for my family of parts? What kind of spindle horsepower and torque will my type of work consume? The first set of questions above is relatively easy to answer, but the second group requires a better understanding of lathes in general.

There are several things to keep in mind when you are in the market for a new 5-axis machining center. To be successful, you must make sure that the machine will fit all of your needs, not just your current one. Often times the purchase of a 5-axis machine is driven by a particular job or part, and sometimes shops fail to consider the other work they could run on the machine. Remember, size does matter.

If you're a regular reader, you're up to speed about the interview I conducted with Mr. Roch, co-founder of Hurco (you can scroll down to this week's video and skip the recap of Parts 1 and 2).

Last week, I posted Part 1 of our History of Hurco video series, where we learned about all of the events—good and bad—that led Mr. Roch to start a business with his boss at the time, Ed Humston. Mr. Roch ended up working in sales for Ed Humston who owned E.L. Humston Company when he quit his job as an industrial engineer at EMPCO in protest of the company president’s, who he believed was making a number of missteps—and his father owned 30 percent of the company, which made the situation even more awkward.

When we hear the term "High Speed Machining" (HSM), most people associate it with mold making, but what people fail to realize is that this technology is being used effectively by shops of every kind to positively impact the bottom line...and isn't that what everyone wants???

I couldn't let the month of October end without acknowledging our 45th birthday...it was October of 1968 when Mr. Roch asked Mr. Humston if he wanted to start a shop. Hurco co-founder, Gerald V. Roch, inventor of CNC and conversational progamming, sat down with me so I could document our company's founding…and he didn't "sugarcoat" it. He talked about failed product launches, financial challenges, and the times he feared the company would fold. During the coming weeks, we will post different parts of the interview with Mr. Roch. To skip the blog article and go straight to the video, scroll to the bottom!

In today’s industry it’s all about quick setup and changeover between parts...especially in an environment where you run a high-mix of low volumes. In this article I want to discuss how part and tool probing can offer a real advantage for the shops that find themselves in this type of environment.

It's that time of year again...figuring out how to keep more of your money for your business. Our friends at Tech Financial sent us the latest information on this year's Section 179 Federal Income Tax Deduction...it's not as great as the 2011 Section 179, but it's still money in your pocket. REMEMBER, we are not accountants so please check with your accountant to confirm eligibility for tax benefits.

Earlier this year, I reviewed the results from the Benchmarking Report by Modern Machine Shop called TOP SHOPS and promised to give you an update when the 2013 results were published. This blog post only touches on a fraction of the information contained in this incredibly extensive report—the Executive Summary alone is 22 pages—so I encourage you to explore Modern Machine Shop’s TOP SHOPS ZONE

For the past ten years or so, we have seen 3D printing technology – also called Additive Manufacturing – really gain momentum in the industry. In fact, it has become so common-place that there has been speculation by some that it might actually replace traditional manufacturing in the not so distant future. Although I can see many benefits of this amazing new technology, and although I do agree that it will someday impact our lives – such as how we, as consumers, acquire many common household items - I have my reservations about how much it will ultimately change the need for traditional manufacturing processes as we know them. Because of the limitations on mixing printing materials, and the fact that the materials available for use in printing are not always the best for a particular application - not everything that can be printed, should be printed.

A few months ago I published a two-part series on the basics of mill-turn technology, where I covered topics such as: axis configurations, the orientation of live tooling holders, mill-turn terminology, instances when a Y-axis might be necessary, etc… In today’s article I want to discuss the differences between the driven tool mounting configurations, and offer my opinions on the benefits and challenges associated with each one.

Regardless of a particular OEM machine tool builder, there are several common machine configurations for 5-axis CNC machines that are available - and each one has its own set of strengths that make it stand out among the choices. The most common types are: Table-Table, Head-Table, and Head-Head configurations.

Hi Hurco Blog Readers. Mike Cope has been on the road quite a bit so I'm filling in as a guest writer for his blog.

When programming in 5-axis, we have two distinct options that we can use to command rotary moves and positions. We can output the data using either rotary angles, or tool vectors. Although each one has its pros and cons, I would prefer to configure a postprocessor to output these rotary commands as IJK tool vectors, instead of the more common ABC axis rotary angles, if given a choice.

Have you ever had to abruptly stop your machine, in the middle of running a program, and wished there was a way to recover exactly where you left off - even if you were in the middle of all that code? For years Hurco’s Recovery Restart feature offered operators a way to just that…but you had to know exactly what block you ended on to recover. Well not anymore! The WinMax version 9 software – which was released at IMTS last year – offers a new feature that will automatically insert a restart marker at the exact location of the last block executed before the interruption - which relives the pressure on the operator to remember (or guess) what block to restart program.

As machinists we are all aware of the standard tools of our trade; however, there are other non-standard tools available - that not everyone is aware of - that could be very helpful in our day-to-day life in the shop. Just like any other industry, if there is a time consuming and mundane procedure that must be completed, you can bet that somewhere there is someone who has already invented a tool or device that would make that task easier…if we only knew where to go to find those tools.

As many of you are already aware, the Absolute Tool Length method of tool calibration has become the industry standard for measuring and recording the length of individual cutting tools on milling machines. This method of tool measurement not only produces numerical values that make sense to the operator, and can easily be verified with a pocket scale, but will also allow for tool lengths to be set offline using a presetter - and then the data can simply be entered into the tool setup for that particular tool…helping to reduce setup time at the machine.

I was recently asked by a reader to post an article about using subprograms. Although this is a pretty simple subject, it made me realize that not everyone is familiar with the use of subprograms and subroutines, so why not offer my input. I will also touch on the use of Hurco’s conversational NC Merge capability…which is powerfully simple and very useful!

In the last blog article we touched on the basics of mill-turning technology. Today I would like to build on that basic foundation. One area of confusion to many operators is tooling – especially the tool holder orientation descriptions (radial tools vs. axial tools). Hopefully we can clear that up a little bit for some of you who struggle with it. I would also like to discuss the use of different tooling options to conserve turret stations when running parts that have lots of features and cutting operations. Machining intricate parts without running out of tooling stations is a common struggle when creating parts on a mill-turn machine.

On a pretty regular basis I am asked to explain something pertaining to live tool machining on a lathe - or Mill-Turn as it is commonly referred to in the industry. Even people with a CNC turning background are sometimes a little confused and can find their understanding a bit cloudy…especially in the areas of tooling, and when the use of an additional Y-axis is necessary. In this article I will try to shine some light on the basics of live tool machining, and the application of the optional Y-axis. In a future article, I will discuss tooling, toolholders, tool orientations, and the differences between VDI and BMT turrets. 

A few months ago I posted an article explaining the CNC motion control system, and how it works. In that article I tried to keep it very simple and breakdown a quite complex piece of technology into an easy to understand analogy…today I want to discuss it in a little more detail, and point out some exciting advances in motion control technology.

I recently received a request from a reader to talk about what is under the sheet metal on the Hurco machines, and to discuss the components that make them so rock solid. Having been a fan of Hurco machines for quite some time now, I am happy to oblige this request.

Just like any other form of technology within our industry, 5-axis manufacturing has its very own vocabulary and list of technical buzz words. Although many of the features described below can be viewed as common, some are only found on the more advanced machine controls. For anyone looking into 5-axis machining, understanding these buzz words can be a huge benefit - and just might keep them from making an uneducated decision that they might live to regret later on.

A common misconception about the Hurco control is that it is a conversational control. This couldn’t be farther from the truth. Although Hurco invented conversational programming - and arguably has the most powerful conversationally capable platform on the market - I certainly would not refer to the WinMax control as a “conversational” one…I would, instead, call it “multi-lingual”.

Just like the plethora of tool axis and collision control parameters that we discussed in last week’s blog article, CAM systems also have a diverse selection of toolpath strategies to choose from - and each of them have their appropriate place in 5-axis. But just like everything else in multi-axis programming, the programmers experience, and the actual machine configuration will play a big part in the selection of the suitable toolpath for a particular application. As I mentioned before, if you asked ten different programmers to program the same part, the outcome is likely to be ten completely different machining strategies. Other factors, like the number of pieces to be machined, the allotted time for completing the project, the specified material, and available tooling can also play a significant role in the toolpath selection process; but the skill level and experience of the programmer will always have the greatest impact.

If you asked ten different 5-axis programmers to program the same single part, you would most likely get ten different machining strategies. Depending on experience, machine configuration, CAM software, tooling, workholding, and a myriad of other criteria everyone sees the path they need to travel just a little bit differently. But they all lead to the same place…a successfully completed part. This article will be part one in a multi-part series about 5-axis programming. 

In an effort to keep this blog interesting and useful, I am asking for input from my readers. Please comment below with topic ideas that you would like to read more about, and that you would find helpful and informative. 

I was recently asked to explain the motion control system, used in CNC machine tools, to someone in my family. Realizing that this individual didn’t have a background in manufacturing at all – and certainly had no experience with anything this complicated and technical  – I had to relate my explanation to something common and simple, allowing them to easily visualize the analogy….like driving a car.

For some reason 5-axis machining just scares people. While talking with people at trade shows, or when discussing the potential of a customer’s parts being a good fit for 5-sided machining, you can just see an uneasy feeling begin to overwhelm them, and you can see the fear begin to well up in their eyes. The mere thought of all of those axes moving at one time, sends them wanting to run for the hills. But if we take the time to look at it logically, and break it down to what is really happening, it isn’t scary at all!

For many years Hurco has offered an easy conversational solution for programming simple 3D geometries, at the control, without the need for expensive CAD/CAM software…but with today’s WinMax control it’s even easier and more powerful than ever before!

 High speed machining is usually associated with any spindle speed above 15k rpm, but it is much more than just a faster spindle. The whole machine must be considered when selecting a good candidate machine for HSM. Thermal compensation, overall machine rigidity and construction, positional feedback, the motion control system, tool retention, and many other characteristics must be looked at, in detail, before determining that a particular machine is suitable for the task.

If the past few years have taught us anything, it's that the addition of 5-axis technology - even in shops that only run "3-axis" work - can positively impact a company’s bottom line. On average, shops who take advantage of this technology have seen improvements of 20% to 30% in efficiency. Imagine…what would a twenty to thirty percent reduction in cycle time and setup time - on a part that you are already running in your shop - mean to you?

Even though 5-axis machining has become much more prevalent in today’s manufacturing market place, and although the overall knowledge base of machinists and operators has grown by leaps and bounds over the past several years, there is still a great deal of misunderstanding and mystery surrounding accuracy – both as it applies to the workpiece itself, and also how the overall positioning of the rotary axes of the machine might be effected.

For anyone new to 5-axis machining, it should quickly become apparent that fixturing can be one of the single most challenging tasks that you will face during the setup process. Although there are many different styles of professionally manufactured workholding devices available, from a variety of different manufacturers - like Kurt, Raptor Workholding, Lang, Jergens, Bock, Hirschmann, and System 3R just to name a few - creativity is the name of the game.

Hurco is well known for our powerful and easy to use conversational software; and for 2D and simple 3D geometries, the WinMax conversational control simply can’t be beat. But what about those jobs that share both simple 2D features and complicated 3D shapes - that can only be programmed using CAD/CAM software? Well, Hurco has an answer for that as well.

In the past, when programming rectangular shaped geometries on the Hurco control, in which the four corners weren’t square or didn’t all have the same size radii, the feature needed to be programmed using a Milling Lines & Arcs data block. However, with the introduction of the latest WinMax mill software, this obstacle has become a thing of the past.

Have you ever needed to make the same dimensional change to multiple conversational blocks in the same program…and cringed at the thought of tediously changing them one at a time? Well, cringe no more! Hurco’s Modify Dimension function makes this a simple task.

When programming a part we often need measurement data that just isn’t on the print - and short of some very involved Trigonometry, or redrawing and analyzing the part in a CAD system, there hasn't been a good way to find these reference dimensions…until now!

Hurco’s patented ASR feature (Automatic Safe Repositioning) is a very powerful tool for 5-axis NC or CAM programmers. One of the biggest problems when posting 5-axis NC code is configuring the post to always output safe, reliable data to reposition the tool-tip without causing the machine to travel out of limits on rapid moves, and to display those annoying error codes that we all love to hate.

There are a number of features built into today’s modern CNC controls that are designed to make life easier for the programmer, and each of these has its own special place in our personal box of “go-to” tools; tools that we use to be more productive. For me, Hurco’s Absolute Tool Length feature is one of those tools that I just can’t live without…and why would I want to?

​Hello, and welcome to the Hurco blog. I will be updating and posting something new each week on a variety of different subject matter: high-speed and 5-axis machining, workholding, the latest control technologies, and Hurco tips-and-tricks…just to name a few.