I'm working on a new layout for an area in my plant in which the operators will run two machines simultaneously. After starting machine one, the operator will then walk over and start machine two's cycle. The machines have a 10 second cycle time so the operator walks back and forth between these machine's all day. I've got a new layout in which the machines are directly across from each other which cuts the walking distance down drastically, but at the same time I know the operator would have to turn around 180 degrees before walking to the next machine every cycle. Is this a serious ergonomic concern? Any ideas?

Thanks,
Andy

Hi Andy

I'd be happy to put in my 2 cents having done many of the same sort of projects in the past...
But I'll need a little more info if you can give it:

Can you give a description of the process that the operator has to do?
Is it simply start a machine every 10 seconds or is there loading/unloading or other operations involved?

What do the machines do?
How big are the machines?
Including other operations that the operator has to do what is the real cycle time needed to meed production demands?

I'm not a big fan of a 180 degree turn - especially if the operator has to make that turn every 10 seconds. But it all depends on machine and space constraints.

Hi Andy

I'd be happy to put in my 2 cents having done many of the same sort of projects in the past...
But I'll need a little more info if you can give it:

Can you give a description of the process that the operator has to do?
Is it simply start a machine every 10 seconds or is there loading/unloading or other operations involved?

What do the machines do?
How big are the machines?
Including other operations that the operator has to do what is the real cycle time needed to meed production demands?

I'm not a big fan of a 180 degree turn - especially if the operator has to make that turn every 10 seconds. But it all depends on machine and space constraints.

Sure, the operator loads a disc, then the machine sands it, then the operator flips the disc and the machine sands the other side, then the operator unloads the disc.
The sanders vary in size, but are roughly 4 feet wide by 3 feet deep and they're waist high.

The machine cycle time is 10 seconds, but the process cycle time is 27 seconds(10 seconds for the top side, 10 seconds for the bottom side, and 7 seconds of in which the machine isn't running because the operator is at the other machine, etc.).

The takt time is 10 seconds, but note we have 4 machines(2 operators).

I'm seriously consider having the machines at 45 degree angles so the operator only has to turn 90 degrees, BUT it will mean the walking distance will increase slightly.

Thanks,
Andy

Andy, being an electrician, I tend to see life in terms of wires..:tg:

What about putting a junction box with an interposing and time delay relay. Put two start buttons for regular use (like you do now) and add another that starts the one, and with time delay, starts the second?

At least that would cut out all the running back and forth for starting.

If you're big enough organization to have an internal electrician, $150.00 materials. Outside job: depends on the area, union, etc.

Sure, the operator loads a disc, then the machine sands it, then the operator flips the disc and the machine sands the other side, then the operator unloads the disc.
The sanders vary in size, but are roughly 4 feet wide by 3 feet deep and they're waist high.

The machine cycle time is 10 seconds, but the process cycle time is 27 seconds(10 seconds for the top side, 10 seconds for the bottom side, and 7 seconds of in which the machine isn't running because the operator is at the other machine, etc.).

The takt time is 10 seconds, but note we have 4 machines(2 operators).

I'm seriously consider having the machines at 45 degree angles so the operator only has to turn 90 degrees, BUT it will mean the walking distance will increase slightly.

Thanks,
Andy


Seems the machines are too large to perform the job seated...
Can that be a consideration if they are placed at a right angle?
Maybe one of those "standing" chairs?

Personally I'd prefer an extra step or two over turning around in circles all day. Safety wise if you're at 90 degrees you can peripherally see either machine and have less chance of bumping into something.

My main concern with the 180 is the frequency. That's a whole lot of turns over the course of a day.

Andy, being an electrician, I tend to see life in terms of wires..:tg:

What about putting a junction box with an interposing and time delay relay. Put two start buttons for regular use (like you do now) and add another that starts the one, and with time delay, starts the second?

At least that would cut out all the running back and forth for starting.

If you're big enough organization to have an internal electrician, $150.00 materials. Outside job: depends on the area, union, etc.

Haha, that'd be a great idea except the operator has to manually flip the disc over before sanding the other side.

Seems the machines are too large to perform the job seated...
Can that be a consideration if they are placed at a right angle?
Maybe one of those "standing" chairs?

Personally I'd prefer an extra step or two over turning around in circles all day. Safety wise if you're at 90 degrees you can peripherally see either machine and have less chance of bumping into something.

My main concern with the 180 is the frequency. That's a whole lot of turns over the course of a day.

I hadn't considered doing the job sitting down. The machines are at least going to be 36 inches apart because there is a 36" wide converyor beside the machines; the operator must have access to this conveyor because this is where the finished discs will go.

I can see the concern as well. I'm having a hard time deciding which is better to the bottom dollar(e.g. its hard to quantify the 180 degree turns' effect from an ergonomic perspective).

Thanks,
Andy

That'd be a great idea except the operator has to manually flip the disc over before sanding the other side.

True, however you're talking about ergonomics. Each repetitive activity you can minimize, the better. You can do a number of simple things to reduce repetitions. They would still have to flip the disc, but you could cut down on them pushing those two buttons forty thousand times a day. Also, you might could use foot switches; that might cut down on the hand/finger movement.

True, however you're talking about ergonomics. Each repetitive activity you can minimize, the better. You can do a number of simple things to reduce repetitions. They would still have to flip the disc, but you could cut down on them pushing those two buttons forty thousand times a day. Also, you might could use foot switches; that might cut down on the hand/finger movement.

The machines were actually originally built so that an operator wouldn't be necessary. They could load, flip and unload the discs all by themselves. Apparently they proved to be too unreliable so they stripped them down for manual operation(all of this before I joined the company).

The machines were actually originally built so that an operator wouldn't be necessary. They could load, flip and unload the discs all by themselves. Apparently they proved to be too unreliable so they stripped them down for manual operation(all of this before I joined the company).

The next thing I was going to ask about investing in automation and having one operator monitor 4 machines.

I believe the technical term for this is "cutting of the nose to spite the face". But, of course, I don't know the full details. It just when I've seen this happen it's been an extreme reaction to something a little patience and training would have resolved.

The machines were actually originally built so that an operator wouldn't be necessary. They could load, flip and unload the discs all by themselves. Apparently they proved to be too unreliable so they stripped them down for manual operation(all of this before I joined the company).
…don't get me wrong, but if those machines were built that required no operator, and it came out that they become “unreliable” that forced you to assign an operator, then I guess the next move you should have done is communicate the problem to your supplier… before you did something internally…

…those machines are originally designed to be unmanned (that’s why I’m sure that they are costly than the machines that requires operator)… if you will assign operator, you are somehow changing the intended design of those machines… and you paid an "extra" for nothing...

…the point is, hit the “root-cause” of the problem… not the stem… :cool:

…don't get me wrong, but if those machines were built that required no operator, and it came out that they become “unreliable” that forced you to assign an operator, then I guess the next move you should have done is communicate the problem to your supplier… before you did something internally…

…those machines are originally designed to be unmanned (that’s why I’m sure that they are costly than the machines that requires operator)… if you will assign operator, you are somehow changing the intended design of those machines… and you paid an "extra" for nothing...

…the point is, hit the “root-cause” of the problem… not the stem… :cool:

Yeah, I understand what you're saying. After doing some more research, I found there was another reason for chaning the machines to be run with an operator. There's more capacity when running the machine with an operator loading and unloading the parts. I assume an engineer long before me did a study that found it was better(financially speaking) to pay someone to operate the machine with an increase in throughput. But this was a decision made long before I started working with this company.

I understand you predicament… anyway, the most common way to solve your problem is to do time & motion study… so you can determine your ergonomic requirements… and based on your situation, you may have different requirements from other, so it would be better if you'll study your actual process to come-out with more appropriate ergonomic requirements, of course, suitable to your process...

In all safety, ergonomics and process improvements drive towards engineering controls as well. PEMEP
Automation somehow would be the ticket.