Integrated CAM with HSM Express

Autodesk recently purchased HSMWorks, a Computer-Aided Manufacturing (CAM) company that developed a completely integrated solution for SolidWorks. It did not take too long before Autodesk Inventor HSM integration became available and users got their first glimpse of 100 percent CAM integration from the company.  While the full-featured product is still not available to us, the Express version is already in use.

Let’s take a look at Inventor HSM Express, and what Autodesk has in store for use with Computer-Aided Manufacturing (CAM).

Article Contents

The HSMWorks Purchase
HSM Express Interface
CAM Job Setup
Tool Library
Post Processing
Closing Thoughts

The HSMWorks Purchase

The recent purchase of Autodesk HSMWorks was quite a surprise to many, but makes sense in numerous ways. HSMWorks offers a truly integrated CAM solution for SolidWorks, with 5 axis mill as well as lathe support. The entire package is completely supported and stored inside the SolidWorks design environment. Every aspect of the software design was built modularly, and as such offered a great way to port the product over to other software, including our very own Autodesk Inventor®.

Speculation has arisen at what will become of the product line, and if the company would jettison SolidWorks support. So far that has not been the case. In fact, Autodesk just released the 2014 product version of HSMWorks for SolidWorks, and we still have not seen any evidence of an Inventor build, which brings us to HSMWorks’ very interesting and free milling product.

HSM Express

HSM Express is a nifty 2.5D milling application for SolidWorks that offers decent toolpath creation, tool management, and post-processing for CAM users. It behaves similarly to HSMWorks, and stores all the toolpath data inside the respective model files. 
While there are other products on the market that are more powerful, more refined, and capable, they lack three very important aspects of software design:

  • Complete integration
  • Inventor Support
  • FREE

Autodesk recently released Inventor HSM Express support for Inventor, pulling the rest of us into the CAM support fold. While I felt that the product must certainly be nearly useless, I could not have been further from the truth. I was surprised at the simplicity and overall capability.

HSM Express Interface

HSM Express is added into Inventor with two main interface changes:

  • CAM Browser
  • CAM Ribbon Tab

Figure 1: CAM ribbon tab layout.

The user interface is quite simple. The CAM tab offers the main functions of a CAM operation:

  • Toolpath
  • Job (coordinate system)
  • Drilling
  • 2D Milling
  • View
  • Management (including tool library)

Figure 2: CAM browser layout.

The browser catalogs the operations into a standard tree-based format. From here, any of the operations can be edited, reordered, and deleted as needed.
Picking an operation from the browser caused Inventor to overlay the toolpath visually on the part in the graphics window. This is quite nice when trying to find an operation, or for me, visually verify that the toolpath is going to behave as I expected. (More often than not, I missed something and have to correct it.)

The operations of CAM and modeling are not mutually exclusive. The modeling environment is still active and a fully functional part of any workflow. With [fully] integrated CAM, there is no mode that you have to exit out of in order to make a change—something I found annoying with earlier integrated CAM solutions). The modeling environment is a completely functional part of Inventor at any moment.

CAM Job Setup

The HSM Express Job is a container for operations within a specific Work Coordinate System (WCS).

Figure 3: Job setup—very easy-to-use tools.

As the application is limited to 2.5D, there is no methodology for connecting any two WCS, nor their operations. Subsequently, new jobs have to be created to accommodate any alternate axis operations in a typical 3D mode.

Figure 4: Browser with multiple WCS jobs. Notice how the stock highlights when the job is selected.

In this example, I needed three WCS job containers to accommodate the internal contouring, the rear face, and front face operations.

Establishing the Job WCS is fairly simple.

Orientation of the UCS can be specified by the following:

  • Model orientation
  • Axis selection from model features
  • WCS selection

Origin is established with these options:

  • Model Origin
  • Selected Point (on model)
  • Stock Box Point (by pick or pull-down)
  • Model Box Point (by pick or pull-down)

Specific Model Solid is selectable as well, which can come in handy for multi-body components.

A stock is developed automatically around the component. Offsets can be selected to alter the stock and its relationship to the final model. Unfortunately, this is simply a box and no round stock type option is available, nor is there the ability to select an overall solid to represent the stock.


The operations that are available are as follows:

  • Drill
  • 2D Adaptive
  • 2D Pocket
  • 2D Contour
  • Face
  • Slot
  • Trace
  • Thread
  • Bore

Of these I was able to evaluate Pocket, Contour, Face, Slot, and Drill.

To add these, pick the CAM operation desired and Inventor will prompt you with a dialog that contains all the operation settings:

• Tool
• Geometry (model)
• Heights
• Passes
• Linking

Figure 5: The eights option set—very easy to configure.


Select from numerous tools already loaded in the library, or add your own.


Selecting geometry for each operation is quite simple and the interface is fairly well tuned for ease of use. The trick here is to learn the order of selection and how the software expects you to select these. Once that’s understood, things get easier to perform.


In the image above, you can see the dialog options and how Inventor overlays each plane in the graphics window. Used carefully, the Heights dialog combined with offsets can offer users a very flexible option that can help tune difficult to establish toolpaths, such as broken up 2D contours.


Passes contains the nuts and bolts options that we come to expect at a minimum: Features such as roughing, stepdown, feed rate smoothing, overlaps, offsets, and so forth.

Figure 6: The pass options


Linking contains the options related to lead-in and lead-out operation, ramp options, as well as rapid movement behavior.

Tool Library

The tool library is a nice feature for a free CAM tool and offers some surprising touches.

Figure 7: The tool library dialog and editor. Notice the layout and the open documents section near the top.

Tools can be selected from the existing library or new tools and holders can be created. Selection filters are available to select by type, material, coolant, as well as the library in which they are included. 

Figure 8: Tool cutting geometry definition.

Each document’s library information is available, so tools from one file can be reviewed simultaneously and copied into other documents. Each holder is cataloged as well, and it is quite easy to create your own. Coolant options can be assigned to each tool and default feed rates can be implemented. This is a nice option as it automatically populates each operation with the tool’s specification feed rate and speeds.

Figure 9: The Feed and Speed dialog—great calculator layout.


The simulation aspects of HSM Express are fairly straightforward. The tool, holder, and stock can be shown, and an entire job or each operation individually can be simulated in the graphics window. The original model can be compared to the remainder stock, and interior corners and overall operation can be reviewed easily.

Speed-up and slow-down options are available, along with additional options. My favorite things in the options dialog are the statistics, which help me get a picture of how long the operation is taking, and how much time I may have shaved off with toolpath adjustments.

Figure 10: Simulation in the graphics window. Settings dialog not shown.

Post Processing

The post processor in any CAM application is critical. All the niceties of CAM can be had, but if you cannot get the information in a useful manner to the machine, it’s all for nothing.

Figure 11: Post processing

The post processor with HSM Express is quite nice. Mill definition files are available, or can be customized as desired. My mill controller software was custom built by a software vendor, and they kindly added an HSM Express definition file. I was delighted to find that it was already furnished in the HSM Express install, as were numerous others.

The post processor picks out key options in tools such as coolant and tool changing operations and seems to process them very well. I discovered this when an automatic tool change came up during a dry run on my mill. After investigation, I found that I had left that option on in the tool definition, instead of changing that to manual.

HSM Express also offers a review utility for digging through your output NC code. It is quite handy, as it can parse through the code and take you to tool changes, etc. The kind folks even included a list of definitions that the post processor will create.

Closing Thoughts

HSM Express is free, and while the mantra holds true that you get what you pay for, this is one of the best free deals I have ever encountered.

The biggest drawback I found was the stock setup. I thought that I should be able to select my stock from another solid body, or at least have a round stock option, but this was not the case. I did have some difficulties with open-ended pockets and unconnected 2D contours. However, these operations were easily worked around using numerous other options, and I never found one I couldn’t perform. But this is why CAM operators get paid to work out the kinks.

It is not yet stated what Autodesk intends to do with HSMWorks for Inventor, nor how they will use this technology in the cloud. However, there are numerous hints given in the Autodesk University 2013 class outlines containing “CAM in the Cloud.”

Would I recommend this application to anyone who needed 2.5D support? Sure!  That’s why I am using it myself.

Here’s a link to a video of our mill running from files developed with Inventor HSM Express:

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