Reply

Small fillets

June 24th, 2018, 1:15 pm

Brian_Donlin
step three
step three
Posts: 130
Joined: June 3rd, 2015, 11:21 am
Location: Chicago
When it comes to small fillets (<4mm radius) for a handheld product, I sometimes have a hard time figuring out what’s appropriate for the design. It might look right in CAD, but I’m never sure if it’s going to look or feel right in real life. What’s your approach for this? Is there a rule of thumb I’m not aware of? I want to CNC an aluminum “fillet reference” to keep at my desk so I can make these decisions on the fly... does this exist already?
D1D6EB82-4BF8-427A-AFF6-585A27886D38.jpeg
FilletRef

Re: Small fillets

June 24th, 2018, 4:03 pm

User avatar
ralphzoontjens
full self-realization
full self-realization
Posts: 854
Joined: February 3rd, 2010, 10:20 am
Coroflot: 76078
Location: Tilburg, the Netherlands
In reality fillets always come out optically a bit larger.
If it is on a negative mold cavity, I usually do not go under .35mm. Anything over .5 is already a significant fillet making an object appear rounded rather than crisp with just the sleek light lines on the edges.
A fillet at 3mm is already substantially large that we have to apply a continuous curvature or more complex blend.

If you find the guide you describe, let us know!
http://www.id-z.one
IDZone - Product Design || Visualisation || 3D Printing

Re: Small fillets

June 24th, 2018, 4:43 pm

Brian_Donlin
step three
step three
Posts: 130
Joined: June 3rd, 2015, 11:21 am
Location: Chicago
Thanks Ralph. At what size do you start applying a curvature continuous fillet instead of a circular one? Since it’s so easy to do CC fillets in Solidworks now, I guess there’s not much reason to use circular unless you’re at really tiny sizes where the difference truly won’t be visible. Maybe I should make a guide with CC fillets, too.

Re: Small fillets

June 24th, 2018, 4:51 pm

User avatar
ralphzoontjens
full self-realization
full self-realization
Posts: 854
Joined: February 3rd, 2010, 10:20 am
Coroflot: 76078
Location: Tilburg, the Netherlands
Hi Bryan,
The standard fillets are computationally most successful so I usually only apply CC ones above 3mm, that is when you start seeing the difference.
For one-offs or 3D printed items I go for a CC only above 5-6mm. Your guide is especially useful for the tiny fillets since we have less of an idea of how those come out while they do make a large difference even at 0.10 vs 0.20.
http://www.id-z.one
IDZone - Product Design || Visualisation || 3D Printing

Re: Small fillets

June 24th, 2018, 6:38 pm

Nic_Kuipers
Posts: 1
Joined: June 24th, 2018, 6:34 pm
Hi Brian,

I've never come across a tool like this in my work. BUT what I do to emulate the same thing is to use a circle guide (image attached) to estimate the size of the radius that I'm dealing with.

You're right that it's hard to pick fillet sizes, but I generally try and keep it to either very small (up to 0.5) and then larger for styling features (5-10 or more) to make the filleting more purposeful.

Cheers,
Nic
Circle Guide.jpg
Circle Guide.jpg (54.03 KiB) Viewed 1634 times

Re: Small fillets

June 24th, 2018, 7:11 pm

Brian_Donlin
step three
step three
Posts: 130
Joined: June 3rd, 2015, 11:21 am
Location: Chicago
ralphzoontjens wrote:Hi Bryan,
The standard fillets are computationally most successful so I usually only apply CC ones above 3mm, that is when you start seeing the difference.
For one-offs or 3D printed items I go for a CC only above 5-6mm. Your guide is especially useful for the tiny fillets since we have less of an idea of how those come out while they do make a large difference even at 0.10 vs 0.20.
Ok, that’s what I figured. Yeah, tiny fillets are really what I’m most concerned with here, for exactly that reason.

Re: Small fillets

June 24th, 2018, 7:17 pm

Brian_Donlin
step three
step three
Posts: 130
Joined: June 3rd, 2015, 11:21 am
Location: Chicago
Nic_Kuipers wrote:Hi Brian,

I've never come across a tool like this in my work. BUT what I do to emulate the same thing is to use a circle guide (image attached) to estimate the size of the radius that I'm dealing with.

You're right that it's hard to pick fillet sizes, but I generally try and keep it to either very small (up to 0.5) and then larger for styling features (5-10 or more) to make the filleting more purposeful.

Cheers,
Nic
Welcome to the forum, Nic.
A circle guide is helpful up to a certain point, though. That one you posted (which is very similar to what I own) only goes down to 2mm. And you also can’t use it to judge the feel of a radiused edge.

Re: Small fillets

June 24th, 2018, 7:39 pm

User avatar
yo
Administration
Administration
Posts: 17030
Joined: January 5th, 2004, 6:57 pm
Coroflot: 67242
Location: SoCal
I used to use metal radius guides when I was starting out, they can be handy. There are a wide array of options and it can be nice to have something to touch.

https://www.ebay.com/i/122552926272?chn=ps
s-l640.jpg
s-l640.jpg (23.58 KiB) Viewed 1602 times

Re: Small fillets

June 24th, 2018, 8:19 pm

Brian_Donlin
step three
step three
Posts: 130
Joined: June 3rd, 2015, 11:21 am
Location: Chicago
Nice! I’ll probably grab one of those for now. Thanks for posting.
Reply