Press tool lesson idea 2

[Cornishengineer]

Hi guys a while sincemy last post but due to some great tips I got the job as an engineering lecturer . Just fishing for any ideas on any practical lesson ideas on press tools eg bending forming simple tool compound tool progressive tool ?

 

[SomptingGuy]

Diagnosing failure modes/broken tools.

- Steve

 

[ctopher]

I don't mean to nit-pick, but to be an engineering lecturer, good writing would help.

Make sure you use the correct materials for tools going into a press. Too soft, it may crush or deform.
Also, look at expansion rates of materials.

Chris, CSWA
SolidWorks 14
SolidWorks Legion

 

[racookpe1978]

Cook's Rules for Bending Metal.

Rule 1. Metal bends, moves, and stretches under load.
Rule 2. Design means knowing how to USE that bending, movement and stretching to create something that WON'T bend, move, and stretch under the final design load.
Rule 3. Metal must be stretched PAST it's intended final position to get to it's intended final position, but not too much past it's intended final position.

That is, if you only bend it as far as it needs to go, you have not bent it far enough.
If you bend it too far past where it needs to go, it won't go back to where you want it to go until you bend it again. But you must bend it back past where it was supposed to be to get it to bend to where it was supposed to be in the first place.

Rocks and ceramics will crack, cold metal will usually gently and evenly bend.
Cold metal bends faster where you bend it around something stronger.
Cold metal bends where you tell it to, only when you encourage it to bend there. Firmly.

Cold metal - given enough force in a small enough area - will cut or tear.
Sometimes you want tearing, sometimes tearing causes your boss' eyes to tear up.
Cold metal - given less force than tearing - yields to bending and stretching.
Stretching never yields to swearing. You must persuade cold metal by force.

Hot metal bends only where you heat it.
Very hot metal quickly bends where you don't want it to. When you don't want it to.

 

[mfgenggear]

an important rule in metal bending is it's percentage of elasticity. the percentage of elasticity must be high.
therefore it lends itself to be formed or bent.

harden heat treated metal will not bend easily. it will fail.
annealed heat treated metal will bend more readily without failing. EG cracking, splitting, after bending then it must be hardened heat treated to the final required hardness.
sometimes some types of metals will work hardened of the & it will require reannealing otherwise it will fail to do the elasticity.

spring back is a well known condition of metals it must be compensated. and sometimes it's trial & error. some configurations are easily bend into shape. while others the tools must be adjusted. depending on the type of forming.

 

[SnTMan]

Aluminum sheet can often be bent to tighter radii across the rolling direction (often called the grain, in my experience) rather than with it.

Regards,

Mike