Category: CNC Engraver

All things related to Guido the CNC Engraver

History editing in Fusion 360

The 3D View is “Just for Show”

With most editing tools, the document you’re editing is comprised of the things displayed right in front of you. With a word processor, it’s the words; a spreadsheet, it’s the numbers and formulae; an image editor, it’s the pixels. This is also true of mesh-centric 3D modelers like Blender or SketchUp. When you move edges or faces, bore holes, or perform any other operation, you’re modifying the Mesh: a collection of points, edges and faces in Cartesian 3D space. The mesh itself is the document.

But with Fusion 360, the document is composed of the sequence of things in the history timeline (shown at the bottom of the screen). The 3D view in the center of the screen is the result of executing that sequence of operations. The things in the Browser (the hierarchical object list on the left), are also a product of the history timeline sequence. Think of the timeline as the program code that produces your design. As far as editing is concerned, the Browser and 3D view are just for show!

I’ve always thought that ‘history timeline’ was a misleading name. ‘Operation Sequence’ might be better. In real life we can’t yet travel back in time, so the term ‘history’ suggests that it’s merely an informational record of what already happened. Not so! Items in Fusion 360’s history timeline can be rearranged and edited. Learning how to do so is key to getting the most out of the tool.

To get some practice with the timeline, let’s walk though a (somewhat contrived) example: The corner bracket pictured above.

First create a sketch describing the basic cross section profile.

Then extrude with the push-pull tool to create a solid body.

Now create a sketch on one of the sides to describe mounting hole profiles.

And extrude to bore the holes.

Now, we’ll use some of the modify tools. First, add a large fillet to strengthen the bracket.

Add a chamfer to counter-sink the holes.

A fillet to round over the top corner.

Add another for the other top corner.

Add one more small fillet to break the sharp edges.

Well, it clearly needs some work, but let’s review the timeline to see what we’ve done so far. First, make the sketches visible for clarity’s sake (find the sketches in The browser and click the light bulbs). Then click the home and fit buttons to get this view:

Right click the first item in the history (a sketch) and select Roll history marker here. The body will vanish from the 3D view, and the Browser will display just one object; the sketch. Don’t panic; you haven’t deleted anything! Note that the items in the history are still there; they’re just grayed-out.

You’ve moved the history marker to display the model as it was defined at this point. Remember: the history timeline is your document; the 3D view and Browser are just for show.

Click the next step icon to advance the history marker. With each click, the display will update to reflect another operation. When you reach the end the 3D view will reflect the model as defined so far.

We can give the sketches and features more meaningful names. This is a good practice in any case, but is especially useful when getting familar with the history timeline.

Right click each item in the timeline; click rename and enter the following names:

basic profile
basic body
hole definitions
strengthening fillet
corner roundover
corner roundover 2
break sharp edges

To see the names you’ve just entered, hover the mouse over each item in the timeline. The names for sketches also appear in the Browser.

While labeling our history items (sketches and features), I remembered that we rounded the outer corners with two seperate features. It makes more sense to use a single feature, since both of these fillets should always be the same size. That way, if we ever want to change the size we need only edit one feature.

Right click the corner roundover 2 feature and delete it. Fusion will warn that the feature is referenced by other features in the timeline. Click Delete anyway!

Now the break sharp edges round-over feature has a yellow background, indicating that something is amiss. Ignore this for now, we’ll come back to it.

Right click the corner roundover fillet and select edit feature (or just doubleclick the feature’s icon). The fillet dialog will be shown, and the 3D view/browser will reflect the model as it was defined at that point in the history.

The fillet dialog indicates that a single edge has been selected. Hold shift and select the other upper edge. Then release shift and click OK.

Notice that the break sharp edges round-over hasn’t been applied to this new fillet. This is due to the same issue that arose when we deleted the corner roundover 2 feature.

So, let’s have a look. First, right click and choose review warning. This displays more detail about what went wrong. In this case it says: “The edge reference is lost, try editing this feature to reselect the lost edge.”

So, let’s try editing as suggested. Double-click the feature to edit.

Even though the model has the same shape as before, the underlying edges that define the body have changed due to our upstream edit. Notice that it now says two edges were selected (originally there was just one chain of edges). If you press shift these edges will be highlighted. You can clearly see a gap where the redefined fillet is.

Click the ‘X’ next to edges in the dialog box to deselect the edges; then reselect the edge. It will select the entire edge chain again. Once saved, the yellow warning background will disappear.  Be sure to address all warning issues in your timeline! If ignored, they’ll just cause trouble later.

When editing something in the history, we often have to review and adjust downstream features like this. This can be very frustrating if you aren’t familiar with the timeline. With a little practice it becomes second nature, and is a worthwhile skill to attain sooner rather than later.

So, let’s finish our bracket. We need holes and round-overs on the other tab, and our break edges fillet needs to go around the entire perimeter.

We’d like the hole pattern to be identical on both tabs of the bracket. We could duplicate the sketch and extrude operations that we used on the first tab, but if we ever changed the pattern (maybe to use more holes), we’d have to edit two sketches instead of one, and we’d have to be careful to keep them identical. By using a mirror operation instead, we can use a single hole definition, making for simpler adjustments later.

First we need a reflecting plane. Choose Construct/Plane at angle and select the bottom edge at the apex of the bracket. Enter an angle of -45. Then right-click the feature in the timeline and rename it reflecting plane.

Now, click Create/Mirror. Set the pattern type to Features, then select our holes extrude feature (in the timeline) and click OK.

Right click the mirror feature and rename it duplicate holes.

Turn the construction plane display off now, just for clarity.

We’d like to countersink these new holes too, but if you double-click to edit the countersinks feature, the new holes do not appear for selection!

That’s because the new holes did not exist at the time we created the countersink object. Note that the countersink feature appears before the mirror feature in the timeline. You might be tempted to simply add another countersink feature, but there’s a better way!

To fix, let’s move the reflecting plane and mirror objects to an earlier point in the timeline. Press shift and select both features. Then drag the features to the left. You’ll find you can’t go further left than our holes feature. Release the mouse button to complete the move.

This illustrates an important concept: Any feature that references another must appear after the dependent feature in the timeline. In this case, the duplicate holes mirror feature refers to the holes extrusion feature, so duplicate holes must appear later. This also applies to sketches that contain projected geometry: The edges being projected must be defined before the sketch.

Now double-click the countersinks chamfer feature to edit it. Since it now happens after the mirror feature, we can add the new holes to the set of ‘edges’ this feature affects. Shift-select the additional holes and click OK.

Let’s fix the corner round-over the same way. Double-click to edit, then shift-select to add the other two edges.

Finally let’s fix the break sharp edges feature again. Double-click to edit it. Click the ‘X’ next to the edges button do deselect all. Then reselect the edge. This time it should select the entire perimeter as originally intended.

Notice that we did all that cleanup without adding much to our history timeline. We removed one feature, then added two and adjusted a few.

The more natural thing might have been to add a new sketch and another extrusion for the extra holes; then apply the fillet and chamfer tools again. Resist this temptation! The model might look the same, but the document will be larger than necessary, will be more difficult to edit later, and will slow Fusion down.

With our concise model, edits are a breeze. Here’s the original plus 3 variants. Each variant was made by editing a single value in a single sketch or feature.

Remember: The history timeline is your document. The rest is just for show!

P.S. The document comparison I made here is oversimplified. Some bitmap editors like Microsoft Paint modify pixels directly, but Photoshop and Gimp documents contain layers and other high-level objects. A Blender document is actually a mixture of a mesh and high-level ‘modifier’ objects, among many other things. In Fusion 360, the ‘sculpt’ workspace offers freeform mesh-based editing much like Blender. Also, Fusion does store faces and bodies in the document that don’t appear as distinct items in the history. I simplified in order to illustrate my paradigm. I lied only to more clearly illuminate the truth.

CNC Monitoring

At AMT you are supposed to stand over your CNC machine as it is doing a job and pay attention.  Is it hanging up?  Is it breaking itself or the bit?  It is on fire?  These are all important things to know. However sometimes a job takes…forever.  When cutting PCBs the job can take over an hour because I have the bit move so very, very slowly. Faster and the bit shatters into tiny little pieces of carbide all over the room.  Not good.  I’ve noticed for awhile that inexpensive internet webcams are available, think of it as a BabyCam for non baby owners. Turns out this little $30 wonder does a great job. When setting up the PCB to be cut I can put the camera on it, configure it to talk to my phone over the AMT network and I can be upstairs working on say a soldering job of the last PCB while the next one is being made. Very handy.

I would recommend everyone who has long CNC jobs they need to keep an eye on but don’t always want to stand over the device to try out something like this.

AMT’s Brand New Bit Box! – Initial Build and Glue Up

Working with the CNC routers and the woodshop hand routers/drills frequently, it’s become apparent that AMT needs a new place to store our community bits rather than “randomly in plastic tubs” or “wherever we want”

Enter the brand new AMT Bit Box!

Based on a design found in Woodworking Magazine, the bit box is being made out of dried poplar, some half inch plywood, and a whole lot of quarter inch dowel rods.

The example above isn’t quite the final form. AMT needs less a retail style “display” case and more a functional set of modular shelves that can be changed as its needs change. Additionally, we need a badass logo on the front.

Let’s take a look at the build as it happens!


1. Size Cuts and Dado Cuts

2016-06-29 15.33.10
Click to enlarge!

I didn’t take any pictures of the first few cuts on the table saw, but it’s pretty standard except for one thing: dado cuts. What is a dado cut you ask? Simply put, dado cuts use a special stacked blade system attached to the table saw to cut specifically dimensioned holes, grooves, and end sections. The cool perfectly lined sections you see on the side piece in this first picture are the result of dado cuts!

One problem: AMT doesn’t have a throat plate of the appropriate size for dado cuts! OH NO WE CAN’T USE THE TABLE SAW WITHOUT A THROAT PLATE BECAUSE DANGER WHAT CAN WE DO.


2. New Throat Plate for Table Saw!

2016-06-29 15.32.52
Click to enlarge!

Oh wait naw it’s cool guys. I made one really fast, gave it a linseed oil coat and some wax. Now it lives in the shop steward drawer with the other appropriate throat plate sections



2. Checking the Squareness and Design Changes

2016-06-29 16.34.20
Click to enlarge!

Here’s the pieces of the box being squared and checked for consistency and straightness. Making a GOOD, LEVEL, SQUARE box is actually one of the most difficult things a woodworker can do, which is why it’s such good practice for joinery techniques and other basics. You’ll also notice that by this point I had already drilled the mounting holes for the dowel rods. As I mentioned, I modified the original design to give us a more modular set of shelves to work with. There will still be a standard set of drawers just like in the original picture to hold random objects, but the lower and upper shelves will be removable while the bit holders themselves will rest on the dowel shots like the sleeves of your Ikea bookshelf. Want to make a new bit holder for the latest set of bits you’ve purchased? Need to store a specialized set of objects? Just cut a piece of scrap to size, mount the things you want to put in the box, and drop it on the dowels!


3. Use of Forstner Bits

2016-06-29 16.52.22
Click to enlarge!

The dowel holes were cut with the Forstner bit set that AMT has in it’s drill section. In the very near future, these might live in the box they were used to make!

For those interested in different types of bits, forstner bits (like any drill bit) makes a hole in wood. BUT WAIT! While a standard drill bit cuts using a spiraled tip, a forstner bit first centers itself using a small needle-like plunge tip and then cuts a very smooth, flat based hole.

To steal from a woodworking site that knows way more than I do: “Because they’re designed to produce a minimum amount of tear-out when exiting the material, Forstner bits are the best bit for drilling through holes. Forstner bits drill a flat-bottomed hole, making them a necessary tool for many hardware installations where a precise depth of mortise is required.”


4. Sandingsandingsandingsaning

2016-06-29 16.34.32
Click to enlarge!

All those big, flat pieces of poplar required about an hour and  half of sanding with three different grits using my finishing sander and its new wonderful connection to the central dust collection system. That hose connector was about $20 at Rockler Wood Supply, while the connector bridging the hose and the central dust intake was about $5. Both were well worth the investment in saving my lungs, the shop air quality, and cleanup in general.

Shopping Link:

Alternatively, you can roll your own using some PVC pipe, our friendly 3D printer, and some standard shopvac hose.


5. Glue Up Finished!

2016-06-29 19.13.50
Click to enlarge!

The glue up is finished! Looking at the level, you can see it’s pretty dead close to being straight and square even with the ridiculous clamp job we got going on. Now to come back  and cut/dado the doors, drawers, and bit holders. Look for this to be finished by the end of the week, and to be up on the wall by the end of next week.


Claire looking goofy... Terry always looks like that.

3D print meeting wrap-up, May 16, 2016

We had a great turnout at tonight’s 3D print meeting!

Welcome newcomers: Alex, Kevan, Efrem, Nate, Terry and Claire (did I miss anyone?), along with returning guests Enric and Jill.

It was a busy night with a lot happening. We demonstrated a print on the Replicator II, printing a key-holder Nate found on Thingiverse. I brought my delta and demonstrated a simple print on it as well, to show how the workflow differs for the open-source toolchain.

The cool key holder shelf
The cool key holder shelf
The gang, hanging out
The gang, hanging out

Next we discussed design a bit using Jill’s water bottle stopper as an example to model in Fusion360. That’s a great example since there are so many ways to do it. Watch for a future post on how to model the thread.

Modeling thoughts
Modeling thoughts

Enric brought along a few of his electronic-project enclosures for show-and-tell. He’s also been doing some interesting experiments with light-pipes for wearable-electronics.

The highlight for me was Terry and Claire’s new Prusa i3 printer! They got a very inexpensive kit from AliExpress for under $200!, and had just finished assembling when they brought it here. After a bit of testing and fiddling with wires we had it mostly working. Unfortunately it was getting a bit late so had to stop a few inches short of that exciting first print. I sent them off with a list of things to do, after extracting a solemn promise to send us pictures.

Claire and Terry's new printer!
Claire and Terry’s new printer!
Terry and Claire shooting trouble
Terry and Claire shooting trouble

I was very impressed with the quality of the kit; and the price was better than you could do sourcing the individual components yourself. According to Terry, shipping was very fast. I got the impression the instructions were a bit on the thin side, but that’s what we’re here for.

5/19/2016: After I wrote this, Terry was good enough to send me a copy of the digital instruction manual that came on an SD card with the kit.  I must say, It looks a lot better than I expected: 

Prusa kit manual example page
Prusa kit manual example page

Terry and Claire: we’d LOVE for you to write up a review of the kit and your experience building it. I always tell folks how easy it is, but the opinion of a power-geek like me simply can’t be trusted. If word gets out that normal well-adjusted folks like you can do it, maybe more would give it a try.