Strength in part

[Temo]

Hello

So I'm printing this part in PLA, but is a bit afraid of delamination between the layers in the inner corners and in the flat back-wall.

I'm printing it in two pieces, the swinging handle and the mount, but both lying at there left sides. That will make the sidewalls strong, but the back-wall a bit weak I think, so I added a 45 degree fillet, but I'm still a bit worried about delamination.

Should I add some holes(parallel to the front) in the back wall, and use two or three bolts, nuts and washers to hold the layers together?

The inner with of the back wall is 18 mm, total height 104 mm.

Terje 

[A. Elias]

Sometimes I'll add a slight angle to my print with respect to the print bed to get more surface area between the layers.  Looking at the U shaped part, with the z-axis being vertical, change the angle of vertical edge with respect to the build plate.  Change it to 85 degees, or 80 degrees.  You can do this with respect to both x to z and y to z.  I printed a spool holder straight up and it snapped in two between the layers.  I printed it again using this method and it's been solid ever since.  

Thanks,

Adam

[PenskeGuy]

On Wednesday, August 6, 2014 5:14:42 PM UTC-7, PenskeGuy wrote:On Monday, August 4, 2014 12:55:46 PM UTC-7, Temo wrote:

Should I add some holes(parallel to the front) in the back wall, and use two or three bolts, nuts and washers to hold the layers together?

How far does the rod swivel? All the way past parallel to touch the back wall? If not, add some ribs across the part. You could curve the upper edge, so that the rod shape doesn't impact them but allows the contact of the rib to come farther forward up each side wall. They could go straight across or make a diamond pattern with them intersecting each other like a waffle. Also, you can increase the temp and slow the speed to ensure good layer bonding by warming the already deposited layer.

[Temo]

Thank you for your answers.

I'm nut sure what Elias mean, but if I understand him right I will rotate the part in both x and y plane with the side laying down, that would mean support under the part. I find that removing support ruined the part as it bonds to much to the part, even if I set it to coarse. I printed the part with port parts laying down( picture rotated to anti clockwise), so the only week part of it would be the back wall, but I used some large washers  to keep the force spread over the entire with of the back.

Yes I could make some reinforcement in the upper part. The part only rotate in the left lower quadrant, see the photo.

Buy the way, are there some tricks to get the support to not bound so hard to the printed piece?

Terje

[Timmay]

+1 to PenskeGuy's comment: Unless you need the upper space empty for some reason, fill it in with some support ribs or even make it solid.

[Aggresive]

Generally getting the flow 'just right' helps, too much flow, and the support will bond really solid to the part. I still have to use pliers/screwdriver to remove, and it leaves a rough edge, but at least it comes off.

I've also got a blower http://www.amazon.co.uk/gp/product/B008P72SSM/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1 on the print (PWM controlled) so the support layer is cool, which likely reduces bond strength.

lonesock might at some point put in a 'support interface extrusion ratio' which would allow us to dial in an almost 'tear-away' support.