Our G-Wizard Estimator software has a Machine Hourly Rate Calculator.   A lot of shops use the notion of hourly rate on machines to help with job cost estimation and quotation, but there’s not a lot of information available about how to calculate a good hourly rate to use.

Here’s what the CNC Machine Hourly Rate Calculator looks like:

The basic strategy is to determine the machine’s Total Cost of Ownership (TCO) over its useful life and then divide that by how many hours it will be used.

Let’s go over each piece of data that must be entered:

–   Purchase Price:    This is the china cnc machining cost and its basic tooling.  For example, a mill will probably need a vise and a few other pieces of basic tooling.  Fixtures used for particular parts should not be included here.

–   Finance:  Check the box if you want to finance the machine.

–   Depost:  The amount you’re putting down on the machine.

–  Loan Term (yrs):  How many years will you finance it for.

–  Annual Interest (%):  What interest rate is the financing?

–  Total Loan Interest Paid:  This just tells you how much loan interest will be added to the Total Cost of Ownership.

–  Useful Life (yrs):  How many years until you’ll be ready to trade-in the machine?

–  Trade-in Value:  What will the value of the machine be when you’re ready to trade it in.  If you wonder, take a look at used machinery prices for similar machines.

–  Annual Consumables Cost:  This is the cost of tooling, lubricants, repairs, spare parts, and whatever else you’d like to include.  Some shops want to bill all the laser cutting machine into the consumables cost while others want them as a separate line item by job since tool wear can vary quite a lot from job to job.

–  Operator Rate/Hr:  The hourly rate you’ll need to pay this machine’s operator.

–  Working Hours/Day:  How many hours a day will you run the machine?  8 is the default.  If you have multiple shifts using the machine, it’ll be more.

–  Working Days/Year:  Will you operate the machine every day or some subset?

–  Downtime (%):  Budget some percentage of time the machine will not be in use.  Perhaps due to needing repairs, because work gets slow, or some other reason.

–  Total Cost of Ownership:  This factors in all of the above costs to give you a Total Cost of Ownership

–  Markup (%):  Some shops will want to apply a profit margin directly to the hourly rate of each machine.  Others will keep it as a separate line item.  You can do either by entering a value here or leaving it as 0%.

–  Hourly Cost w/ Labor:  This is the final number to come from the calculation.

The numbers in the example were for a Haas Mini Mill that I just took the information of their web site for.

You can find the Machine Hourly Rate Calculator on the Machine Profile under the Setup Basics tab.  Each machine has an Hourly Rate field.  Next to the field is a Calculate button that brings up this calculator:

 How Can You Use Machine Hourly Rate When Estimating Jobs?
When you estimate your jobs, using a Machine Hourly Rate that’s calculated based on each of the different machines needed to make the part will help ensure your job estimates are more accurate.  What you need to do is combine the Hourly Rate on a per machine basis with your estimate of how many hours will actually be needed from each machine.

G-Wizard Estimator helps you build a simple spreadsheet to do this.  It estimates how long each machine is in use via the CADCAM Wizards that are built into both G-Wizard Calculator and G-Wizard Estimator.  Only the version in Estimator can do these estimates though.

The CADCAM Wizards make it easy to do feature-based time estimates.  Here’s a screen shot of the CADCAM Wizards in GW Estimator showing just the inputs you’ll need to make to get an estimate:

It’s pretty straightforward and there are relatively few inputs needed:

Machine
Material
Feature
Feature Parameters
The Features are just the different types of operation you might perform–pocketing, 2d Profiling, boring holes, facing and so on.  The goal is to be able to look over a print of the part you’d like to estimate and enter each feature quickly and easily.  The CADCAM Wizards try to minimize the number of questions you have to answer to get a complete Feeds and Speeds recipe.