Laser Shaft alignment Pump, gearbox input outputand motor 1

[bmw318be]

Hi

I have some doubts on laser alignment of pump to gearbox and Motor.

While aligned the pump and geaebox, after vertical adjustment is within tolerance, I moved to the horizontal alignment while leaving the vertical bolt snugged.

Thw result,after horizontal adjustment, the remeasured show the Vertical is out of tolerance.

Is there a tips should i add shims make it slightly higher before torque it down.

It just did not get consistent alignment after every horizontal adjustment.

 

[TugboatEng]

If the alignment is changing as you torque it down you have a soft foot and need to shim it correctly before proceeding with the rest of the alignment process.

 

[FacEngrPE]

Agree with Tugboat, Laser alignment is much more sensitive to soft foot, than manual methods of alignment.

 

[bmw318be]

Hi Thanks,

You are right, I did the following

1. Do vertical alignment check while bolts loose,
2. It prompted you the number of shim thickness below 4 points.

The prompts did not factor in yhe soft foot as each of the front foot 2 points may have softfoot more than the other, so I did exactly ehat you tell me

Not following the prompt of thickness from laser alignment, I correct the obvious softfoot

Next, i would torque down slightly and check if the reading is constantly change, it it is, I would find the possible soft foot in all 4 points.

The issue is sometimes, the vertical is settled, the horizontal adjustment required large movement which might move the movable equipmrnt to another plane which has another different soft foot.

How to resolve this issue ?.

 

[TugboatEng]

Run a milling machine over the foundation to make it flat.

Don't use hand cut shims.

Alignment in the field is a trial and error process. Your adjustments should keep getting smaller until everything is dialed in.

 

[edison123]

If the vertical reading keeps changing, may be the motor bed is flexing instead of being rigid.

Muthu

http://www.edison.co.in

 

[FacEngrPE]

Everything is a spring.

If the shims are not flat, the motor feet or the base not parallel, the alignment task is much more difficult, as that makes the spring softer.
[ul]
[li]If using hand cut shims, they will often be bent at the edges where they are cut. If you use several shims stacked, it is a bit like stacking belleville washers.[/li]
[li]If the surfaces the shims are placed between are not parallel, the foot to base by itself can be soft even if the other mounting points are correct. One way to check/fix this is with an old school straightedge high spot bluing, and hand scraping.

or use a milling machine to flatten the foundation.[/li]
[/ul]

It is possible to perform a laser alignment using bent shims, but very tedious.
It is similarly possible to use laser alignment when the mounting is out of parallel, but also tedious, as all of shim thicknesses the equipment suggests will be incorrect. Only do this if you are willing to spend the time to learn to interpret the laser alignment suggested shims to the shims you need. This is the sort of thing we used to get experienced millwrights to do, there are not very many of them.

 

[bmw318be]

Hi Thanks for the inputs, I attached the alignment photo of the equipment's for better discussion.

https://1drv.ms/u/s!AshU1On9Vy6fipV5fodEJqpQr6bXpA?e=YJh05m

Here what is the finding:

1. The Gearbox bolt is not symmetrical in design, shims can only be placed at the back of the gearbox instead from the bolting
2. The vertical alignment of the gearbox is keep jumping as soon as torque down the bolt
3. The laser alignment show the back of the gearbox footing is lower and need to be added by 0.18 and front 0.29 mm, by adding it, it did not bring down my 0.29 mm front footing and make it the front footing more sensitive as soon as the front footing is tighten.
4. Initial soft foot without shims for gearbox is:
1: 0.1
2: 0.04
3: 0.01
4: 0
Pump soft foot

1: 0.06
2: 0.03
3: 0.05
4: 0.03

5. Condition of the spacer coupling is coupled during the laser alignment

6. Baseplate is milled plated on top of I beam

7. Shims design for the gearbox is more than 7 mm.

8. Pump can not be shimmed

9. Condition of the gearbox to motor is coupled with spacer coupling


Do you think, I should decoupled the spacer as is it possible the coupling is preventing the laser alignment from getting a stable results.

The challenges, the vertical can not get a good alignment once torque down, so it is still prone to change as after horizontal is adjusted.

 

[edison123]

Is it one single 6 mm thick + 1 mm of multiple shims? If not, you have got a spring, which will screw with your alignment.

Muthu

http://www.edison.co.in

 

[TugboatEng]

Those are stiff couplings and are likely carrying some of the weight of the gearbox which is why it moves during tightening. I suggest you leave the couplings disassembled during alignment.

Also, you can place shims on the side at #5 even though the bolts won't pass through them. However, I suspect the bolts are distorting the foundation as the gearbox and foundation are not in contact at the bolts.

All of this is due to design error. The 2nd mounting pad is installed in the wrong location. You really should start by looking in to the feasibility of correcting the design error.

 

[bmw318be]

Tugboardeng,

Sorry I did not get your point that I shoupd put the ahim on side at # 5. The 5 is where the shim would support the whole wright of geaebox.

The bolt hole as i said is not symetrical.

I also not getting you 2nd mounting pad is designed in the wrong direction. Which one ?

 

[TugboatEng]

The mounting pad at the arrow is not where it needs to be under the bolt at circle. You need to cut off and relocate mounting pad for best results.

As it's unlikely that will happen, you can still shim as necessary between the gearbox and the mounting pad at arrow. Expect some movement as you tighten bolts. You may be distorting the gearbox, though. Check your pattern after alignment.

 

[electricpete]

good point Tugboat about lack of support below the holddown bolt.



=====================================
(2B)+(2B)' ?

 

[FacEngrPE]

This is not a very stiff support frame. As it looks like you need it to be portable, consider that picking it up, and moving it to another location on a reasonably flat concrete floor, will change the alignment. You might be able to see this by stepping on the corners of the base with the alignment kit attached to the shaft.

These light weight bases usually depend on the concrete floor for some of their stiffness. I have seen them filled with concrete to make stiffness + inertia block so they could be placed on top of vibration isolation pads.

Once you get the best alignment possible, and get some service time, I suggest you consider a future coupling type change - when the current coupling fails, not now. Gear, grid, and flexible insert couplings all are more tolerant of misalignment than the flexing disc type (they have their own good and bad points, so consider which - if any will serve better than the current choice).

 

[dArsonval]

The photograph showing all three pieces of equipment mounted to a frame weldment suggests that it is not in its final operating location.
It somewhat looks like a temporary setup for installation elsewhere.

But here's some more to consider:

Once the three items are zeroed to dead-on alignment… a new headache will show-up after the equipment runs for awhile and heats up.

The high-speed end of the gearbox could run warmer than the low-speed end.
Actually, the entire gearbox will “grow” horizontally… and the hotter end will grow more than the other end.

Let’s say for sake of discussion… the motor runs 30 to 95 degrees C, the gearbox temperature increases more than
the motor temperature to say…65 to 82 degrees C… and the pump “shrinks” if the pumped fluid is cold… to say, 10 to 21 degrees C.

Thermal growth for the motor is vertically up, while for the gearbox… it’s horizontal... and at the same time the pump moves down.

This all means the assembly will run smooth at start up until it comes up to operating temperature… which by then…
it will be out of alignment and vibrating.

So… factor this additional headache when aligning these three pieces of equipment.

John

 

[bmw318be]

Hi,

Appreciate for such a great suggestion,

@FacEngrPE

It is temporary setup testing, in actual site, the frame would be filled with epoxy grouting on 4" C channel after alignment and actual pipe is hooked up.

I noted on suggestion of Tugboat that I should place the shim inner on the holding bolts.

 

[BriggTrim]

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[bmw318be]

Hi,

Thanks for the advise, I have moved the shims to the machine bolt and it is easy to align now with coupling on.

 

[TugboatEng]

Thank you for the follow-up and props to your team for being open to modification.

 

[FacEngrPE]

Careful alignment is tedious, but well worth the effort. Thanks for the feedback.