×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Machining operation (fillet) on Aluminium block

Machining operation (fillet) on Aluminium block

Machining operation (fillet) on Aluminium block

(OP)
Hi all,
I have Aluminium block which is drilled from 2 sides at 90°.

Problem:
A sharp edge is created at intersection of both the operation.
Due to this there is a pressure drop. We did a CFD analysis for this.
So for this we need to add fillet/radius at the intersection zone. (on the edge)

I need to know, what is the process by which i can get the fillet at the zone.
Also need to check its feasibly for high volume parts.
Please refer the attached pdf which indicate the requirements.

regards,
Sundeep

link to file:
http://files.engineering.com/getfile.aspx?folder=3...

RE: Machining operation (fillet) on Aluminium block

I would finish the drilling off with a ball nose cutter in one direction,

RE: Machining operation (fillet) on Aluminium block

(OP)
but still the intersecting edge would be formed.

RE: Machining operation (fillet) on Aluminium block

Okay maybe I am not understanding what you are after correctly. If you are looking at putting a chamfer or radius on the inside edge where the two meet that is more of a problem.

Whilst it will not put a true radius or chamfer on have you considered abrasive flow machining? Basically it involves forcing a type of abrasive “putty” through the inside of parts to improve the surface finish / remove burrs, similar end product to “rumbling”.

RE: Machining operation (fillet) on Aluminium block

I would be surprised if that edge is causing significant flow loss compared to that caused by the 90 deg turn. It may not be worth the effort to solve. What is your fluid and flow rate?

Ted

RE: Machining operation (fillet) on Aluminium block

You can probably rough out that interior fillet with a ball cutter in a CNC mill, but the cycle time will be very slow because you need a reduced shank cutter to get in there. It will require handwork to get a nice finish; in fact there may be no penalty for doing all the cutting with handheld Dremel tools.

Or go for the abrasive flow machining.

Depending on the particular aluminum alloy in use, you might be able to machine the elbow bore in a straight condition and bend the part after machining. You will probably have to use a larger bend radius than you have shown, and neck down the outside pre-bend.

If you are at a fairly early stage of development, you owe it to yourself to spend some time in a junkyard and look at how automotive air conditioning stuff is assembled from aluminum tubing with end fittings that are coined or formed or machined from extrusions, and everything crimped and brazed and then bent, etc.



Mike Halloran
Pembroke Pines, FL, USA

RE: Machining operation (fillet) on Aluminium block

You could modify the design to change the 90 degree to a large angle if possible. You could also use oversize end fittings on the hose connections and increase the bore diameter of this 90 degree thus increasing the area slowing the fluid around the corner, reducing the pressure drop.

I would not try to change the corner inside the part. They will have a hard enough time removing the burrs in the area you are concerned about. The bending concept of MikeHalloran is also interesting.

Bill

RE: Machining operation (fillet) on Aluminium block

For cross-hole deburring and interior edge radiusing, I'd recommend one of these tools: http://www.deburringtechnologies.com/
Most are suitable to CNC cycle programming which can be done in large quantities with consistent results. There are a few other internal deburring tools out there which might work the same. Call some vendors, get them to bring samples by and help with the application.

good luck.

RE: Machining operation (fillet) on Aluminium block

Quote:

Also need to check its feasibly for high volume parts.

If you're going to high volumes, you may also want to look at making the entire block as an aluminum casting and machining any threads for fittings, etc afterwards.

You can achieve the internal fillets with a core fairly easily.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources