The FARCE that is Feature Based Cost Estimating

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Taking a trip around the net you might find a few of the machine shop job costing and estimating software applications out there touting their application as “FEATURE BASED” estimating. My first reaction is always … REALLY ??? Does anyone really fall for that sales gobbly-gook speak ???

What else would you want to estimate … 

With further thought it becomes abundantly apparent that it simply sounds good … makes for a good sales pitch … catches the eye … but the reality is … don’t be fooled. As a professional think about it. If you have a part with a variety of “features” that need to be machined … the simple act of estimating the time to machine those features … WHICH IS REALLY ALL THE ESTIMATE IS BEING CREATED FOR … is the act of feature based estimating. THERE ISN’T ANY OTHER TYPE !!!

And What About Those Features ??

AND … if you are touting feature based estimating you better be able to handle ALL kinds of features … not only simplistic milling and turning of simplistic parts. Real world workpieces have odd shaped pockets and contours … odd shaped turned parts with various types of grooves and undercuts. Simplistic “feature based” estimating app’s simply don’t handle the “real world” well.

AND … this is not a “fluff it off” input either. Watch some web demos and you’ll see the demonstrator utter the famous words … “OK let’s say that’s 10 inches.” Great for a demo but how did you get that figure? If they don’t show you … they must be hiding something … like it’s really hard to obtain.  This input is just as much at the heart of an accurate estimate as insuring that the speeds and feeds used accurately reflect your shop floor cutting parameters … not just some “book knowledge”. Our KipwareCYC® has been tested and developed on real shop floors and we have hundreds of clients who purchased our KipwareCYC® after having compared their actual machining times against times created with KipwareCYC®. You don’t get any better than that. And the system we have created using the tool’s length of cut … is by far the most accurate way to estimate cycletime … and our Cut Length Calculator app is the easiest and most accurate way to calculate that length of cut.

Accurate speeds and feeds without accurate tool engagement time produces inaccurate estimates as well.

There is really only two ways to calculate the amount of time a tool is engaged in the cutting process … and therefore determine the cutting time for the tool. Those inputs are (1) measuring volume of material being removed and (2) tracing the tools length of cut while doing the cutting.

Using Volume of Material Removal as an input Is NOT REALISTIC !!

If the machining time estimating software is using an input related to volume of material being removed … that should be a RED FLAG. Why?

  • FIRST – Volume of material is NOT an indicator of the time a tool is engaged in the cut. And calculating the time the tool is actually engaged in the cut is the BEST way to determine cutting time. This type of input does not accurately reflect the tools time of engagement … because the tool may follow an unorthodox path while cutting … and that takes time.
  • SECOND – it already assumes that you have or are going to create a CAD drawing of the workpiece … and an accurate, to scale drawing at that. What if that’s not the case … as in about 85% of work that gets quoted in the real world. From sketches, from drawings that are not to scale, from prints … the volume input is next to impossible to obtain without an ACCURATE – TO SCALE CAD drawing … so you’ll need to create a CAD drawing.

Using Extends or Outline as an Input

The most accurate input for determining a tool’s length of time or engagement in the cut is the length of cut input. Why? Because this input actually traces the tools path while in the cut … which may not consist of “standard” type movements as reflected in the simple volume of material being removed.  This input is a little tougher to achieve … a little bit more of too much and it will be overkill … but you can get much closer to the actual time of engagement with this method. BUT … the toolpath must be accurately reflected for the calculation. Having a part that has a non-standard outline and saying that the extends are 6 x 3 is NOT accurate enough. You need to trace or follow the tool will take around the contour to insure you are as close as you can get. As mentioned above … our Cut Length Calculator app which comes standard with KipwareCYC® is by far the most accurate way to obtain a length of cut … using either a conversational, fill-in-the-blank format … or a DXF input.

Take a look at “feature based” estimating on STEROIDS in our KipwareCYC® – CUT LENGTH CALCULATOR video … the link is below :

Soooo … let’s Review

  • “Feature based estimating” is really just the act of creating a machining cycletime estimate … since you are really only creating the estimate so you can tell your customer how long it’s going to take to machine the part, and the associated costs. DON’T BE FOOLED.
  • The most accurate way to estimate cycletime for machining is yto utilize the time of engagement for the cutting tool. Volume of material being removed is a very subjective and inaccurate input and a tools length of cut is the most accurate.
  • KipwareCYC® is coupled with the Cut Length Calculator application and can provide users with a quick and accurate length of cut for traditional, standard operations for BOTH milling and turning … or utilize a DXF file so users can accurately trace the path the cutting tool will take around a non-traditional shape … giving closest length of cut calculation without the overkill.

If you agree with the points we have outlined here … we welcome your thorough review of KipwareCYC®, the companion Cut Length Calculator application and for costing … our KipwareQTE® software.

For additional information on the complete KipwareCYC® – Machining CycleTime Estimating Software application … CLICK HERE.

AND … for complete information on turning that cycletime estimate into a complete COST ESTIMATE and QUOTATION … check out KipwareQTE® … CLICK HERE.

Kenney Skonieczny – President
Kentech Inc.