How long does it take?

The DLC Shop is asked many times how long it will take to make a part. This reasonable question is difficult to answer. Lets look at an example.

This is a rather simple part.

Sealing-Disk extract

How many hours would it take to manufacture it?

One simple method to estimate the amount of time is to count the number of manufacturing operations.

  1. Bring disk to correct size diameter
  2. Bring disk to correct thickness
  3. Four holes
  4. One Large Hole
  5. Surface finish and deburring

Now assign an amount of time to each operation. Include part setup in machine tool, machine tool setup for speeds and feeds, tool to hole location, surface grinding, edge deburring, tool collection, “oops” or “gosh darn-its”, and measurements of each finished operation.

  1. Diameter – May take about 45 minutes if the stock is originally 3 inches in diameter.
  2. Thickness – May take about 30 minutes
  3. Four Holes – 60 minutes on manual machine or 20 minutes on a CNC machine
  4. Large hole – 45 minutes
  5. Finish work – 30 minutes

This totals 3.5 hours for this simple part. Now add in a material – Steel, Aluminum, Stainless Steel, Alloy, or Brass and the attendant machining complexities.

There are many ways to shorten manufacturing time. This part could be made quicker by purchasing stock of the selected diameter. A blank disk could be located and purchased from a supply house and modified. I will talk about this in another post…

You should not use scrap or trash stock because it is immediately available. This expands the amount of manufacturing time by the machinist having to bring the material to the starting or “near net” shape of your object.

Machinists are a precise bunch who pride themselves on making precision and accuracy happen. Squaring up a block or whittling a piece of scrap down to size can take hours of numbing labor. This mind blowing, grinding, dulling labor later detracts from the concentration needed for making the fine adjustments necessary for perfecting your part.

Additionally, the extra manufacturing time adds up. It in turn affects other jobs in the work order task list and that work order may be yours.

Near net shape.  Please keep this in mind as you are working on your design.

My 2 cents. – An Engineer


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