CAM Software CNC program estimated cycle times.

Here’s an observation that we hope you will find interesting.

The use of an image of a mechanical stopwatch is no accident. Back in the day, we didn't have timers in our pocket and we had no means of accurately estimating the cycle time. We had to go and time things manually so that the job could be accurately booked.

Thank goodness for changes!

The question of cycle time calculation accuracy is important.

In any CAM system there are, as you might expect, many settings that can be used to influence the cycle time. In SmartCAM there is even a ‘fudge factor’ that can be automatically applied to the result, because often the estimated time will prove to consistently be ‘n%’ out.

But these things cannot really be guaranteed to be accurate. There are just too many intangibles, too many synthetics.

But ..

Here is were SmartCAM can help!

 

There is some neat stuff in SmartCAM that can be used to help deliver an accurate cycle time calculation.

It’s like most things: if that cycle time is critically important to you then it’s worth spending some time in trying to get it as accurate as is possible. If you’re not bothered about the output cycle time, then why bother wasting time on setting it up.

Let’s have a brief look at what is available in SmartCAM.

The Code Generator Machine Define tool has settings for machine tool linear and rotary rapid traverse rates, tool index times, that adjustment factor mentioned above, and more.

These settings are used to create a cycle time when graphically verifying toolpath and also when generating code by running the post processor code generator.

A good application-use example of them is a when experimenting with one toolpath / production method over another, the difference in the resulting cycle times can be helpful.

Cycle times can be output according to needs; as a message block in the code file or in a setup document, to mention but two examples.

SmartCAM Customizable Job report

Fine Tuning
Now, if you were tasked with creating accurate cycle time calculations from SmartCAM and the system-generated time didn’t cut it, then you could do more...

The Code Generator toolkit also uses a template ( *.cgt) file which controls how and when addresses are output and so much more.

CGT files have sections; the code generator and code generator writer ‘knows’ when code for key events such as start, end, line, arc, rapid, tool change ( and other events, too many more to mention here ) is being generated.

Here’s about the most basic example, a linear move section:

// Linear feed move.

@LINE

< #MOV>< #DCOMP>< X#XPOS>< Y#YPOS>< Z#ZPOS>< F#FEED>

@

CGTs can also contain logic programming. It is very feasible and actually quite simple for a Code Generator creator to add logic to their CGT file that manages cycle time output (and most stuff, for that matter) to high levels of accuracy; adhering to standards that are uniquely theirs or those of the company.

The CG (Code Generator) has a variable for the length of the linear move (meaning that you don’t even have to include logic to work that out using previous and next positions), and it can get to the feedrate being used for the move. Counting the incremental time for a linear move is very simple. Something like:

// Linear feed move.

@LINE

< #MOV>< #DCOMP>< X#XPOS>< Y#YPOS>< Z#ZPOS>< F#FEED>

#EVAL ( #mycycletime = #mycycletime + #LNLEN / JOS( feedupm1 ) )

@

( we are using CG commands there, but since this isn’t a training lesson, it isn’t appropriate that we describe that stuff here. Suffice to say that the explanation is pleasingly technical, simple and logical )

And we might want to output a message block containing our cycle time at the end of the CNC code output:

@END

 #SPOFF M09

< #MOV>< #DCOMP>

 ( My Estimated Cycle Time is: #mycycletime minutes )

 M30

@

We hope this gives just a small insight into some of the possibilities.

In addition to managing cycle time at a ‘user level’, when it comes to CNC code requirements CGT logic can be used to output all manner of different things. We never cease to be amazed and impressed by the outputs from SmartCAM that our customers achieve using their preferred CAM system functions.

We like to say that the possibilities are only really ‘limited by the imagination’.

And that is the end of our time for today.


You can reach us at:

+1 (541) 344-4563

sales@smartcamcnc.com

www.smartcamcnc.com

The SmartCAMcnc Team