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Steel Milling

Steel High Speed Machining

This post is about a cute little steel part (yes, steel can be cute) that started as a quick brainstorming session in engineering and resulted in a cool finished product for a Saskachewan electronics manufacturer.  Even the smallest job at Lean Machine can involve all of management, engineering, administration, and of course our machining department.  There are some pretty neat circular machining marks left on the part due to a unique machining method that we will explain below.

This part looks like it could be made from steel flatbar but here at Lean Machine we almost never use pre-cut shapes.  This started as a laser cut blank off our HK Laser then we put it through our Haas VF4 mill and this is the resulting part.  By not using pre-cut shapes we can reduce our inventory (as you can imagine we would almost never have the correct shape and qty in stock) and shorten our lead times because we can custom cut whatever we need out of a large plate.

This part looks like it could be made from steel flatbar but here at Lean Machine we almost never use pre-cut shapes.  This started as a laser cut blank off our HK Laser then we put it through our Haas VF4 mill and this is the resulting part.  By not using pre-cut shapes we can reduce our inventory (as you can imagine we would almost never have the correct shape and qty in stock) and shorten our lead times because we can custom cut whatever we need out of a large plate.

Below is the difference between traditional machining vs high speed.  The idea is to take smaller (thinner) cuts at a faster rate.  We try to achieve a cut with the entire diameter and height of the cutter engaged in order to spread the chip load over the whole tool (instead of just the leading edge).  High speed machining also gets super technical by trying to match your cutting frequency with the resonant frequency of the machine but we will leave the explanation of that for another post.

Here is a pretty accurate description of the old (we'll call it traditional to be nice) machining method vs the new better, faster way. 

Here is a pretty accurate description of the old (we'll call it traditional to be nice) machining method vs the new better, faster way. 

The is a top down view of a cutting tool.  By burying the cutter deep into the material you can take thin cuts that load the tool around more of the diameter which distributes the load evenly.  Dropping the tool down into the middle of the material used to be a scary thing to do if you just tried to plow through as you would quickly overload the cutter and it would break.  Now we can even use smaller (cheaper) tools because they spin faster to eject the chip (and the heat).

The is a top down view of a cutting tool.  By burying the cutter deep into the material you can take thin cuts that load the tool around more of the diameter which distributes the load evenly.  Dropping the tool down into the middle of the material used to be a scary thing to do if you just tried to plow through as you would quickly overload the cutter and it would break.  Now we can even use smaller (cheaper) tools because they spin faster to eject the chip (and the heat).

We use both MasterCam and Inventor HSM to complete our machine programs.  This is a screen shot of what MasterCam calls "Dynamic Milling".

We use both MasterCam and Inventor HSM to complete our machine programs.  This is a screen shot of what MasterCam calls "Dynamic Milling".

Autodesk HSM and Compound Miter Machining

Autodesk HSM and Compound Miter Machining

The topic of the post is two-fold: one, we need to introduce Lean Machine's integration of Autodesk's HSM programming for all of our mills and lathes; second, we want to show a really cool compound miter cut on the end of a steel tube.  Below is a CAD model from Autodesk Inventor.  The really neat thing about HSM is that it allows us to program directly inside of Inventor so there is no need to have a translation file in between CAM (Computer Aided Machining), or a separate CAM program.

The steel tube that we are going to cut has been changed to semi-transparent for illustration purposes.

The steel tube that we are going to cut has been changed to semi-transparent for illustration purposes.

Doing a compound cut would normally require a 4 or 5 axis milling machine.  Instead, we created angled and twisted jaws for our vises.

Here is the finished tube mounted in the vise to show how it turns it on the exact angle so the operation can be completed from just one top cutting plane.

Here is the finished tube mounted in the vise to show how it turns it on the exact angle so the operation can be completed from just one top cutting plane.

This is the top view of the set-up. Note the marking lines on the back jaw to make sure they go back in the machine correctly.  The same marks are in the CAD model, so everything matches when the machinist sets up the job.

This is the top view of the set-up. Note the marking lines on the back jaw to make sure they go back in the machine correctly.  The same marks are in the CAD model, so everything matches when the machinist sets up the job.

This is the top view of the clean precise cut that the mill provides.

This is the top view of the clean precise cut that the mill provides.

These are the front and back vise jaws removed from the vise; they were machined from solid aluminum.

These are the front and back vise jaws removed from the vise; they were machined from solid aluminum.