How to avoid delamination during machining

[Anna]

Hi! We bought some filament wound tubes (0.75 x 1.00 x 12 Inch) and are experiencing some delamination when we turn them down in our lathe (adding taper from 1 inch-0.9 inch). Any recommendations on machining methods (speeds, direction) to avoid this? Thanks!

[lo_0l]

Hey @Anna, welcome to Composites Community 🙂

What kind of tubes are you trying to machine? Did you make these yourself? Or did you buy them somewhere?

[Anna]

Hi! The filament wound tubes are from Rock West composites. We’ve reduced rpms which has helped but any other tips would be appreciated.

[lo_0l]

4 hours ago, Anna said:

Hi! The filament wound tubes are from Rock West composites. We’ve reduced rpms which has helped but any other tips would be appreciated.

Machining composites can be pretty tricky! Can you share which tubes you ordered?

Is the taper itself needed? Or are you just trying to hit 0.9"? Most tubes get sanded to size.

Also, do you have a model of the part you're trying to make? The more information the better 🙂

[Anna]

We purchased SKU: 35047-S and had them cut to 18in. These are jackets for rifle barrels so the taper is needed. We can clean them up pretty good with sanding but it's a bit labor intensive.

[lo_0l]

16 minutes ago, Anna said:

We purchased SKU: 35047-S and had them cut to 18in. These are jackets for rifle barrels so the taper is needed. We can clean them up pretty good with sanding but it's a bit labor intensive.

The only way RWC is able to get the finish they do on those tubes you ordered is by sanding. They don't use a lathe to get the desired diameter. The tubes are sanded to the desired diameter. I don't think you're going to be able to get the finish it sounds like you're looking for without doing some sanding.

Another option is that you could order these from Rock West Composites customized to your liking. It might be a lot easier for them to do it with their equipment.

How many of these do you need to make?

[Anna]

Ah, that makes sense then. We’ll see how efficient we can make our process with the current batch (~70) and consider the custom option for the next batch. 
 

Thank you so much for your response!

[lo_0l]

5 hours ago, Anna said:

Ah, that makes sense then. We’ll see how efficient we can make our process with the current batch (~70) and consider the custom option for the next batch. 
 

Thank you so much for your response!

You're very welcome! Happy to help any way we can.

I'll shoot you an email with a contact for a quote so that you can get that rolling.

PS - do you have any pictures of what you're making? Love seeing what people are up to 🙂