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Stamping press main gear failure - photos
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It will probably be laid off as fatigue stress or a casting flaw, but what I see is a design flaw the keyway should be 90°away from those large holes. which would have placed it between the 2 smaller holes the internal impact stresses would be greatest at the keyway which is in direct alignment with the least amount of material mass
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I bet that make an awful noise!!!!
Also could that have dropped the press on someone?
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Quote:
Originally Posted by
Frank S
It will probably be laid off as fatigue stress or a casting flaw, but what I see is a design flaw the keyway should be 90°away from those large holes. which would have placed it between the 2 smaller holes the internal impact stresses would be greatest at the keyway which is in direct alignment with the least amount of material mass
Not to mention untold potential millions of cycles; though a press that size (maybe 300 ton) is about 15-35 per minute, depending on part size, material feeding and auto or manually tripped. No clue, the dieset is out; wood cribbing holding up the ram. That alone would be a job for the millwrights.
This is called a straight side press, and tiny compared to what auto manufacturers use. Mounting such a dieset, and prepping the machine itself is time consuming, so they run figurative 24/7.
It's possible that it made a double hit (two pieces of material), but only if operator is a Darwin Gold Medalist, scoring 9.8 with all 5 judges. Punching parts isn't as demanding as forming, two sheets eat up all the clearance, the crank still wants to generate same stroke, and whamo!
Glad presses I've serviced were belt drive flywheels!
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Quote:
Originally Posted by
Toolmaker51
Not to mention untold potential millions of cycles; though a press that size (maybe 300 ton) is about 15-35 per minute, depending on part size, material feeding and auto or manually tripped. No clue, the dieset is out; wood cribbing holding up the ram. That alone would be a job for the millwrights.
This is called a straight side press, and tiny compared to what auto manufacturers use. Mounting such a dieset, and prepping the machine itself is time consuming, so they run figurative 24/7.
It's possible that it made a double hit (two pieces of material), but only if operator is a Darwin Gold Medalist, scoring 9.8 with all 5 judges. Punching parts isn't as demanding as forming, two sheets eat up all the clearance, the crank still wants to generate same stroke, and whamo!
Glad presses I've serviced were belt drive flywheels!
One thing I would have liked to see would be a photo of the gears at the time the housings were opened up, before they cleaned them.
Also judging by the noticeable wear of the shaft hole on the housing cover. It would be a safe bet the main shaft bearings are on the decline as well
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Obviously can been from a longer distance traffic route than the required at the press.
Surely the mold will be having damages as well.
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Quote:
Originally Posted by
kess
Obviously can been from a longer distance traffic route than the required at the press.
Surely the mold will be having damages as well.
Possibly. If it was punching (slugs or blanks) damage might have been minimal as punches have some place to 'go'. If was forming or coining it would be more severe, depending on what caused fracture. You should see what happens when someone leaves a wrench in there. It makes several impressions; on the owner, supervisor, the whole shift, HR department, unemployment office, and toolmaker assigned to fix it......
The conventional term is 'dieset' comprised of punch holder, almost always the upper half and attached to ram. The lower is the die and mounts to bed platen. Finely ground posts in tight fitting bushings set the alignment during the build, storage, mounting, and that lee'ttle extra augmenting travel of the machine itself.
A 'mold' shares some features such as upper and lower halves. The 'punch' is called a core, the 'die' known as cavity. They also carry pins and bushings. In horizontal presses, aligning halves would be next to impossible otherwise. Few injection molding machines run vertically, suitable for only very small parts.
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Quote:
Originally Posted by
Frank S
It will probably be laid off as fatigue stress or a casting flaw, but what I see is a design flaw the keyway should be 90°away from those large holes. which would have placed it between the 2 smaller holes the internal impact stresses would be greatest at the keyway which is in direct alignment with the least amount of material mass
I agree. The opposing side in the last picture has cracks in the same general area and near total failure.
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Quote:
Originally Posted by
redbaron1917
I agree. The opposing side in the last picture has cracks in the same general area and near total failure.
I recently had some failures in a pair of #35 pitch 10 tooth sprockets. These were purchased with a .625" bore .125" keyway the factory had placed the set screw 180° opposite of the keyway, both the keyway and the set screw were located directly timed with the valley of the tooth pattern. I had also ordered some wiht plain stock bore which I was going to bore for bronze bearings as idler sprockets. I told my partner the keyed ones would most likely break before the chain in testing due to the location of the keyways and set screws, which they did the first time we loaded them under stress. So I bored 2 of the stock bore sprockets located my keyways directly under a tooth and located the set screw between 90 and 120° away from the keyway locating it in alignment with a tooth as well this time in testing the master links of the chain was the point of failure, but still lower than what I felt we needed for a FOS for long service life, causing me to have to make some major changes in the design to allow for a double row chain since the smallest 2 strand #35 sprockets were 12 tooth.
Keyway placement and set screws play a huge part in design strength the many don't understand
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Obviously, the two large holes are a major contributor to the structural failure.
