Small holes not being cut during stimulated tool path

[alHSSJ3]

Having problems getting three of the five holes on this part to cut out when stimulating the tool path. 

It is a treadle bar for a rat proof chicken feeder to be cut out using a cnc plasma cutter.    The two 1/4" holes on either ends cut out fine as does the perimeter hole.  The three middle holes are skipped.  Two of the holes are 13" from each end, after the part is cut out it is bent into a U shape  with the two middle holes for wood screws to attach a wooden step, the third hole is 4" from one end and is used to pass a 1/8" wire link through to connect to an axle that allows the depression of the treadle to crank the door open.  The tolerance can be quite sloppy on all three 3/16" holes. I might need to increase the diameter of the two end 1/4" holes if a test part indicates the sides of the holes are too tapered.

https://a360.co/3RZCPnD

I am a complete newbie to CNC, CAD, and CAM so no doubt I am doing something wrong that is quite basic.  I have been browsing this site and it has gotten me this far so this is a great resource, thanks for those that contribute.  I did take a training class on the plasma cutter and it had some basic training on creating the sketch and tool paths but I am stuck at this point.

I haven't tried altering the lead in values for the parts yet so that might be it.  I also wonder if using a hole diameter the same thickness of the stock is the problem, I had read that good practice is 2 x the material thickness.

If the hole diameter is too small, I had read somewhere that the plasma can be used for marking the location of the holes for later manual machining without hardening the mild steel material too much but I neglected to save a link to that info so if it is the hole size can someone point me in the right direction for marking the holes with a pulse from the plasma?

Thanks

Al

[engineguy · Accepted solution]

@alHSSJ3 

First, your file is not downloadable, either you did not set the permissions correctly or you ae on a Free Hobby Licence.

To upload a Fusion f3d file go to :-

File > Export > Select f3d format > Save to a location on your computer > Then attach to your reply using the "Attachments" facility below your reply box.

Meantime have a look at the f3d file attached, I used arbitray values as I didn`t know your tool information, should help as a rough example 🙂 🙂

Regards

Rob

[alHSSJ3]

Thanks for the info Rob.   Yeah, using the free hobby license to see if I can figure out this software before I buy a license.

Looking at the picture the link loaded I see the two end holes have spiffy arrows pointing up and the three middle holes don't.  I drew the part in sketch mode, then extruded it, I was thinking it would extrude all five holes but I am going to go back and delete the holes and re draw making sure I have the hole settings right.

Appreciate your time and effort replying to the post.

Thanks

Al

[alHSSJ3]

Very strange....  I opened up your file and the file I posted and ran your simulation which worked perfectly.  I right clicked on the holes in sketch and looked at the settings on your holes, then looked at my holes in another window.  Exact matches.

Tried the simulation on the original file and the darned thing worked without any changes.

Maybe opening up your file reset something in the preferences?

Many thanks Rob.

Back to learning.

Al

[engineguy]

@alHSSJ3 

Hi Al, the "spiffy arrows" are a Red one for the entry to the toolpath and the Green one is for the exit from the toolpath, the ones in between are Transition moves from hole to hole 🙂

No idea why your original file should start to work all of a sudden, that one is in the "lap of the gods" 🙂 🙂 🙂

Fusion 360 is an amazing software and there are so many things to learn that it can put some folks off but perseverance and lots of visits to this Forum will get you through to a level where you can make good use of the software, a lot depends on just where you are looking to venture to and what you want to do with it 🙂 🙂

There are many very learned folks (Way above my abilities) who will happily help you out with any problems that you may encounter and there will be lots of those 🙂 🙂 🙂

Regards

Rob