Fastening Die on Press Bed

Dowels ?

Ya, shank, dowels, and clamps.

already there is a guiding mechanism

So what? A guiding mechanism isn't a dowel...
<slaps furry head with paw>

Del

as good as a dowel

obviously not

H7g6 fit

AAAARRRRGGHHH..

If it was as 'good' as a dowel you wouldn't have the problem...
If you don't want an answer, don't ask the question!

<slaps furry head frantically with paw>

Del

Miss alignment could be the one cause. Worn die guide pins. Variation in the material thickness another.

An adjustable stop to hold the position of the die under the clamp but will allow movement during alignment.

Pinning it will work as others have suggested. This though allows no adjustment for variations in material thickness. Depending on the complexity of the shape being stamped may jam if material is too thick. Adjustable stop would allow ease of release of the jammed part.

misalignment & worn out guiding surface have been checked for & found ok.

as u had mentioned, it is the variation in material thickness due to the asymmetric profile of the component.

can u give me some more info on adjustable stop or tell me where i can find

SUJAY

Just adhere a thread block to the base the die block is clamped to. Run bolts in to retain it in position and lock them down with a nut.

Hi There,

Been working on press tooling for about 47 yrs, run in anything from hand arbour presses to 1000 ton hydraulics & can never recall tooling " walking" side ways if properly clamped using either plate clamps & packing or step blocks or hydraulic clamping, tee bolts or tee nuts, even with drop-forge tooling which belts the clappers out of the tooling.

If he tool has assymetrical die sections or forms then there can be high sideways internal forces in the tooling itself, thrust blocks etc can eliminate these forces, proper tool design should consider these factors in the design stage . The pillars & guide bushes would have to flex beyond their elastic limit to force the bolsters to move on the platens.

How are your plate clamps fitted to the bolsters, there is a correct way to set them up & incorrect way, set incorrectly the clamps will put most of the clamping force on the step or packing block instead of the bolster lugs or clamp ledges on the bolsters.

Regards,

Brien.

Have seen it a few times. Dieset was seeking a new center.

KesterSujay: Does this movement affect tool-life?

YES !! Any movement or flexing or miss-alignment of tooling sections will affect die life, particularly with cutting sections & small clearances using thin material. Good tooling all boils down to good, soundlly designed & constructed tooling, if your tooling loading is off-centre to the press cenre line the forces will tend to tilt the press top platen particularly with 4 post hydraulic presses, sometimes this is unavoidable but you can use nitro springs etc to balance offset loads.

I always designed tooling on the assumption that it was going to be abused by unskilled die setters & unskilled press operators & on presses that might be in poor condition & not always properly maintained, used to be a bit of a joke in the drawing office that if I designed it to make sure it had plenty of eye-bolt holes so you could lift the bloody thing !! but the tools never broke !!

Brien.

Have you thought about standardizing your dies or is that feasible. By setting the dies up with the same size shoes (dies built in the future) or adapter plates (precision ground not just a scrap piece of stock) you could mount permanent guide rails to your press bolster. This would prevent the lateral movement as well as speed the clamping process during die changes. If your needs change in the future the guides could be removed or altered. Jack screws could also be used in the guide rails to thrust load the die to the side it wants to "walk" to. As mentioned by the guest in post #14 there is a correct way to use bridge and fulcrum (toe clamps) type clamps. The stud should be located as near the die as possible. The fulcrum block should be located far enough away to transfer the clamping force to the die and away from the fulcrum block. Do not exceed the rated load for the bridge. Doing so will cause it to bow and allow the die to move. Use as few washers on studs as possible. Do not over torque the stud assembly. Be sure your studs, T-nuts, and clamping nuts are in good condition. Damaged/dirty threads will give false torque readings. If the person setting the die lacks the upper body strength then use a torque multiplier wrench for final torque adjustments. Another option would be to fore go this type of clamp and use Right Hite style clamps or change over to hydraulic clamps. How much clamping force was indicated by the die designer in order to hold it securely in the press? Or, do you have a rule of thumb for the number of clamps to use in your presses?

Make sure the bolster bolts are tight and make sure there is not a lot of play in the ram.