Hi,
Hope you can help, I want to calculate the MIG welding time on a
manufacturing project using box sections and tube. Can anybody give me
any pointers to calculating a good estimated welding time??
Regards
Alec
If you know the weld geometry then, calculate the weld cavity volume. &
by knowing the density of depositing material with 80 to 90 % dilution
of depositing material in weld bead, find out the mass required of
consumable electrode. As your welding is MIG, we know that, the
deposition rate will be 6 to 8 kg/hr., so divide the mass required
with deposition rate you will get the theoretical welding time.
Weld cycle times are the sum of the actual weld time plus the
positioning time plus the fixture load time. Any or all can be
significant depending on your project.
Weld time on thick sections is limited by the the deposit rate of the
wire feed. Thin sections are limited by fitup issues, triggering, and
the need to dial down the welder to avoid burnthrough. Mid range (eg
1/8" to 3/8") with good fitup is limited by how fast you can move the
weld pool, somewhere around 20 to 30 inches per minute.
Positioning time is simply how fast can you move from one weld to the
next. On a robot, this is typically around 1 second. A person needs to
move, steady, brace, flip the helmet, and fire. Don't forget to either
reposition the weldment or deal with out of position welds. On a large
tubing structure weldment, the arc time can be way below 20%.
I used to model the weld times for potential robot weld centers.
Expected the actual to match theoretical within 3% or so. But that
required every joint to be analyzed.
With as much data as you have given, try 20 inches per minute for all
the weld, multiply by 3 to 5 for positioning time. Can't do any better
without a set of prints to look at. Of course for a modest fee............
alecgreen wrote:
"RoyJ" wrote: (clip) With as much data as you have given, try 20 inches per
minute for all the weld, multiply by 3 to 5 for positioning time. (clip)
^^^^^^^^^^^^^^^
This reminds me of how we used to weight cows down on the farm. You look
for a long straight pole, and balance it on a rail fence. You tie the cow
to one end of the pole, and then look for a big rock that will just balance
the cow when tied to the other end of the pole. You then estimate the
weight of the rock. ;-)
I know Lincoln and Miller have applicable literature.
The one thing I have found useful is to compare the actual time to weld
an assembly and the theoretical time to do the length of welds.
In the type of work I do which is structural most every piece is
different than the next. The operating factor often works out to a ratio of
five to one. A welding time estimated as ten minutes ends up taking fifty
minutes when turning and handling and spatter removal is taken into account.
The most important item learned is that welding time is really not as
important as welding salesman tell you. More time can be saved by good
planning and effective crane equipment and procedures. They will try to
sell you a wire or gas that will increase production. Even if the new wire
or gas increase welding speed by double you only save five minutes out of
the fifty it took you to weld the assembly.
Straight production of hundreds of identical pieces is another matter of
course.
Suit and Ties often make an ignorant comment about how much faster one
welder can weld than the other employees. It isn't the welding that is
faster when everyone has the same machine. What is different is that person
is planning his number of turns and his whole work area to reduce repetitive
handling.
Just my thoughts on welding speed/time.
Randy
Hi,
Hope you can help, I want to calculate the MIG welding time on a
manufacturing project using box sections and tube. Can anybody give me
any pointers to calculating a good estimated welding time??
Regards
Alec
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