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Tuesday, March 10, 2015

Shop Efficiency Part 7 - CNC Programming

Our Shop Efficiency series has really taken off ... and we would like to take a few lines to say Thank You to all our readers for your email comments and support. We are very pleased that we have been able to take some of our real world machining and machine shop experiences and turn them into valuable tips and pointers and pass them on to so many of you. Thanks so much for your support.

First - A little background on this Post
At first glance ... since Kentech Inc. develops and sells CNC programming software ... this post might look like straight marketing and a sales pitch for our Kipware® conversational CNC programming software. Actually ... it's a story of just the opposite. Most of our software titles have been designed and developed based on what we saw was lacking in our many years on the shop floor. Our Kipware® conversational CNC programming software is a product of that experience.

One of my most telling personal experiences was working in a shop here in Masachusetts as a CNC machinist. The shop was your typical job shop with all kinds of work coming through the door. Most of it was fairly simple ... with a few plastic injection mold type jobs every once in a while. The CNC programming was supposed to be done by the shop floor machinists ... using a CAM plug-in for Solidworks ... which was a bit complex. No CAD/CAM training more than a simple tutorial was offered or provided. As a result ... since most shop floor machinists were great at cutting chips but lacked intense CAD/CAM experience ... and the jobs were fairly simple ... they often resorted to manual programming. The result was programs loaded with mistakes ... from typo-errors to incorrect toolpaths ... and the result from that was scrap, broken tools and sometimes worse ... but the overall effect was complete shop floor inefficiency.

The frustration level on the floor ... needless to say ... was very high. The machinists were basically unable to do their job ... because no one trained them on the complex CAD/CAM system ... and there were no other tools to help them ... other than an editor.

In this environment ... our conversational CNC programming concept and design was born. It was plain to see that the CAD/CAM and a CAD/CAM programmer was required for the mold work ... but clearly for the 95% of programming we did on the shop floor it was NOT required. In fact ... having the CAD/CAM option as the only option ... actually made things worse.

CNC Programming and the LINK to Shop Efficiency
Which brings us to this post and the subject of CNC programming as it pertains to shop efficiency. Obviously ... if the program isn't created in an efficient and correct manner ... the parts don't get made and the money doesn't flow. But just as important as tooling and fixturing ... the program creation process must have options also. You wouldn't think of placing a simple rectangular piece of stock in a custom made fixture ... you would use a vise. In the same way ... you shouldn't think of programming a simple part with a round pocket and bolt circle through a complex CAD/CAM system. The real key to efficient shop floor programming is having an ARSENAL of tools at your disposal. Thinking about your CNC programming as more of a tool ... with multiple choices for various situations ... will help your shop floor reach a higher level of efficiency.

CNC Programming Tools Available
We've listed what we consider to be the realistic options for CNC programming available to anyone creating CNC programs in a "job shop" environment ... the environment where our readers predominately are working ... and the options up for discussion in this post.
  1. CAD/CAM
  2. Off-Line Conversational CNC Programming Software
  3. Conversational CNC Controls
  4. G Code "wizards"
  5. Manual Programming through an Editor
"Wizards" and Manual Programming
To narrow the discussion a bit ... let's remove the two options that are really not realistic in a professional machine shop environment. So called G code wizards are way too simplistic and act
more as hindrance and weight than any kind of efficient tool. Full conversational programming software makes much more sense both from a financial and capabilities perspective. Full, quality conversational software is a programming system ... not a simplistic crutch.

Manual G code programming should only be considered for the simplest of parts. Human error plays too great of a role in any other scenario and really renders this option a last resort choice for a professional programming environment.

That's not to minimize manual CNC programming knowledge and experience. Any CNC programming option used is made VASTLY more efficient and productive when operated through the hands of an experienced manual CNC programmer. A good Editor should always be available to allow that experienced CNC programmer the tool to alter or edit auto-created G code. The point here is that creating programs from scratch manually is not a good choice. Even for simpler programming ... a tool that will auto-generate the code provides stability ... and the manual tweaking of the code can enhance that output greatly.

Efficient CNC Programming Requires an ARSENAL of Tools
It's more about OPTIONS than OPTION
In a professional environment ... really the two main options are CAD and / or CAM and full, quality conversational programming software. The CAD/CAM option can really be broken down into two options. First the CAD option is a must for any design environment ... even when that is just supporting the shop floor with fixture design. Professional CAD can range from the simple to the complex ... and from the FREE to megabucks. Each shops design and CAD needs would drive that discussion. However ... going from the CAD drawing to a G code program does not necessarily have to through the expensive and complete CAD/CAM system.

Using conversational software ... that CAD drawing can also be turned into a G code program. DXF import can be used in quality conversational software and a variety of other applications to go from a CAD drawing to a G code program.  And of course ... the integrated CAM option can be used to go from that CAD drawing to a G code program.

The main point is that no two workpieces are exactly alike ... and the right programming option for one will most likely not be the right programming option for another. From our experiences ... the best programming method for any job involves (2) main factors :
  • Who is the best choice to create that program? Shop floor? Dedicated programmer?
  • What is the best tool for that individual to use to create that program quickly and accurately?
Letting the correct answers to these questions guide the process ... rather than forcing the path because of limited options ... will increase your shop efficiency when it comes to programming your CNC's. Some thoughts :
  • Maybe the best person to create the program is not full CAD/CAM proficient but would be the best chip-maker for the job ... a shop floor conversational programming option might be the best solution. 
  • Perhaps the job is very complex ... and the only solution for an accurate and efficient toolpath is the CAD/CAM alternative. 
The point to make is that with an arsenal of tools available ... the experience of your personnel and the complexity of the workpiece / programming can dictate the most efficient path to take for the program creation. This allows for the free flow of efficiency ... rather than ramming the square process through a round hole.

Machine Tools with conversational CNC controls
Conversational CNC controls mounted directly to a CNC machine appear to be the perfect solution ... but actually have some important points to consider. The alternative of purchasing a laptop or Windows based tablet ... loading it with conversational software ... is more often than not the better alternative. Here are our major reasons to support this claim :
  1. CHEAPER ... conversational CNC controls can be quite expensive. A tablet with conversational software will cost less than $1200.
  2. PORTABILITY ... having the ability to do the programming on the shop floor, in the office, at home ... makes a portable alternative very attractive.
  3. PROGRAM MULTIPLE MACHINES ... the ability to simply move the laptop around or pass it off to someone else gives you the ability to use the "conversational control" on multiple machines. Other machines can also be purchased without the conversational option ... you already have a "conversational control".
  4. PROGRAMMING AT THE MACHINE ... even though most modern conversational controls have basically (2) modes ... the conversational programming mode and the machine operation mode ... they can often result in headaches and frustration. Either the machine is not runnning waiting for a program to be created ... or the machinist is programming the next job while trying to run production. Not the best environment to say the least.
  5. CNC CONTROLS ARE NOT COMPUTERS ... most industrial grade CNC controls do not have the power or capability of a desktop or laptop PC ... they are simply not constructed from the same components. And if they are a PC ... they are most likely NOT an industrial grade PC and not fit for the harsh machine shop environment.
  6. CONVERSATIONAL SOFTWARE IS MORE POWERFUL ... backed by the power and capabilities of a PC ... conversational SOFTWARE is more powerful and has more options than conversational software operating on a CNC control.
Some Closing Thoughts ... 
The main reason for combining this post into our Shop Efficiency series is to get shops thinking about all the potential programming tools available. Our experience shows that the most efficient CNC programming is accomplished when an ARSENAL of good tools are made available. Inevitably users might find and use their favorite tools ... but the key is that they have the ability to choose from an assortment. Also ... that the other tools remain available when the need arises ... providing choices. Also ... when an assortment of tools is available ... shops can increase the number of people who can create those programs ... and that is a huge jump in shop efficiency. Creating CNC programs faster ... using more people ... means more spindles turning and that means more profits being generated. And isn't that the true test of Shop Efficiency?

Please come back for our next installment in our series on Shop Efficiency.
Until next time ... Happy Chip Making !!

At Kentech Inc. we are MACHINISTS who create Real World Machine Shop Software.
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