Rotor balancing in Porto and Vila Nova de Gaia: based close by, serving the whole country

AXILINE is based in Vila Nova de Gaia, on the left bank of the Douro, close to the industrial areas of Porto. We come to your site with Balanset instruments, measure vibration on the bearing housings, and balance the rotor in its own bearings — no removal, no sending the wheel off-site. Around Porto and the north, the drive to your site is short, so coming back for a follow-up measurement is easy. That said, we do travel across all of Portugal — such visits are simply planned in advance.

Updated 27 August 2026 · by AXILINE · Vila Nova de Gaia

Where we're based and where we travel

Base address: Rua das Colectividades 76 R/C ET, 4430-625 Vila Nova de Gaia. This is where the engineer sets out from, and where the kilometres are counted from. We have no branches or representative offices in other cities, and that's more honest for you: you always know where the vehicle is coming from and what travel you're paying for.

Porto, Gaia and the neighbouring municipalities are our near radius. Here the drive takes less time than setting up the instruments on site, and we're happy to take on a job for a single machine. Beyond that comes the north: Matosinhos, Maia, Valongo, Santa Maria da Feira, Paços de Ferreira, Braga, Guimarães, Aveiro, Viana do Castelo, and the industrial zones along the A1, A3 and A4. A visit like this usually fits into a single working day, provided the window for test runs is agreed in advance.

The centre and south, from Coimbra and Leiria down to Lisbon, Setúbal and the Algarve, are also within our reach. There we simply plan the visit with extra lead time and try to fit several machines into a single trip — yours or a neighbouring plant's — so travel doesn't eat up the budget.

• Near radius: Porto, Vila Nova de Gaia, Matosinhos, Maia, Gondomar, Valongo, Espinho.
• North: Braga, Guimarães, Santa Maria da Feira, Aveiro, Viana do Castelo, Vila Real, and the industrial parks along the main motorways.
• The rest of Portugal: we travel by arrangement, planned in advance.
• We calculate distance by the road route from our base in Gaia, not as a straight line on the map.

The advantage of this region is how dense the industry is. It often turns out there's another fan or pump with the same complaint on the next street, and the second machine costs less than the first: the travel and the minimum invoice are already covered by the first job.

What it costs and how travel is calculated

The price is set by the size of the rotor, not the make of the machine. We split the work into four packages and only add on top what you actually ordered: a second correction plan, higher precision, a written report.

• Minimum invoice per visit: 500 EUR. Package S on its own doesn't reach that minimum, so for a single small machine the invoice will still be 500 EUR.
• Minimum time on site: 4 hours. This isn't a rush surcharge — it's the time it genuinely takes to take the initial measurement, run the trial starts, and verify the result.
• If your own staff carry out the fitting and welding work, it's included in the price — there's nothing extra to pay for it.
• Payment: 50% in advance, the balance after the work is done.
• All prices are shown + VAT.
• We calculate the travel amount for your address and fix it in the quote before the visit.

Choose the precision grade by the job, not out of habit. For most industrial fans, pumps and crushers, the base precision included in the package is enough, and the extra cost of G2.5 or G1.0 won't pay for itself. It's worth checking the applicable grade and edition of ISO 21940 for your specific rotor type — there are separate provisions for rigid and flexible rotors.

Sources: ISO 21940-11:2016 · ISO 21940-12:2016

Who calls us most often in this region

Requests around Porto and the north repeat from one industry to the next. The machine changes, but the reason is the same: the rotor has picked up unbalance in service, and the vibration has started loading the bearing housings around the clock.

We don't publish names or figures for specific sites. If you need to know whether we've handled a similar machine before, call and describe your unit, and we'll give you a straight answer.

Typical equipment in the region, and where to look next

For each type of machine we have a dedicated breakdown in the equipment section: where the correction planes are (the spots on the rotor where balancing weights go), what gets in the way of balancing, and when weights won't help. Below are the machines most common in northern industry, and the material where each one is covered in more detail.

• Fans, induced-draft fans, blowers and cooling-tower fans: see the breakdowns on balancing fans, centrifugal and axial machines, and blowers.
• Pumps: breakdowns on balancing pumps, pump impellers, and multistage pump rotors.
• Electric motors: balancing motor rotors, balancing a rotor after rewinding, balancing armatures and generators.
• Size reduction and processing: balancing crushers, hammer mills, shredders, mills, chippers and wood crushers.
• Drives and transmissions: balancing pulleys and couplings, belt-drive pulleys, cardan shafts, shafts and drums.
• Machine tools: balancing machine-tool spindles and grinding wheels.
• Separation and drying: balancing centrifuges and separators, and production-line equipment.
• Agriculture and forestry near the city: balancing mulchers, forestry mulchers, threshing drums.

If your machine isn't on the list, that's not a refusal. The requirements for the rotor are the same for all of them: stable running speed, access to the correction plane, and a confirmed dominance of the 1x component — the vibration at running speed. A separate article on the conditions for balancing covers the borderline cases.

How quickly we can come: an honest answer

We don't give a specific timeframe until we've looked at the calendar and understood your situation. That's not modesty on our part. Balancing requires runs at working speed, and the bottleneck is almost always not our schedule but your window: the line needs to be stopped, the area cordoned off, and an electrician and a fitter scheduled onto the shift.

So the conversation runs the other way round. First you tell us when the machine can actually be stopped and started, then we confirm whether we can make that window. That way the date holds, instead of slipping a second time in a row.

The near radius has the advantage here. From Gaia, the engineer reaches a site in Porto or Matosinhos in about the same time it takes to set up the instruments, and it's easier to slot into a window that suddenly opens up than it would be on a trip two hundred kilometres away.

• What speeds up the visit: a ready window for stopping and starting the machine, access to the correction plane without removing the guard, your own fitter on site, and a site access permit already arranged.
• What stretches out the timeline: an unknown cause of vibration, no mounting spots ready for the sensors, the need for scaffolding or a lift, and coordinating the work across several departments.
• What we do before the visit: go through your photos and figures, assess whether it's unbalance or another cause, and tell you upfront if it's too early to come out.

If the 1x component doesn't dominate your vibration, a balancing visit will be a wasted day. In that situation we say so plainly over the phone and suggest starting with vibration diagnostics rather than weights on the impeller. Separate articles cover how unbalance differs from shaft misalignment, and when balancing won't help at all.

Sources: ISO 13373-3:2015

What to prepare before we arrive

Preparation takes you an hour and saves us half a shift. Everything on this list genuinely affects whether we finish within the minimum 4 hours on site, or turn one visit into two.

• Agree on a window in which the machine can be stopped and started several times in a row. There will be at least three runs.
• Provide access to the correction plane: a hatch that opens, a removable cover, or an opening in the shell (the cylindrical housing). If there's no access, tell us in advance — it changes the work plan.
• Prepare mounting spots for the vibration sensors on the bearing housings: flat, cleaned metal free of paint and dirt, so the magnet seats firmly.
• Provide a spot for the reflective marker on the shaft or pulley, and a clear line of sight for the laser phase sensor.
• Provide a 220 V outlet near the machine for the laptop and the module.
• Clean any build-up off the impeller if it's visible to the eye. There's no point balancing a dirty rotor — the unbalance will come back with the next bit of build-up.
• Check and tighten the fasteners on the feet, frame and foundation, and eliminate any obvious play. A soft foot — a loose fit between the machine's foot and the frame — ruins the result more reliably than any error in the calculation.
• Settle who provides the fitter and welder: done by your own staff, it's included in the price; done by us, it's an extra 150 EUR per rotor without welding or 400 EUR per rotor with welding.
• Prepare the site passes, the work permit, the start-up lockout and the area barriers. Your site's safety requirements come before our schedule.

A detailed breakdown of the preparation, including choosing measurement points and mounting the sensors, is in separate articles on preparing equipment for balancing, on vibration sensors, and on the phase sensor with the reflective marker. Read them before the visit if this is your first time.

The advantage of a short haul

A short haul means a short drive from our base to your site. Its main advantage isn't the price of travel — it's the ability to come back. Balancing isn't always a single trip. Sometimes the machine needs checking at operating temperature a week later; sometimes you want the result confirmed after it's run a full shift under load.

We keep the influence coefficients for your machine — exactly how its rotor responds to an installed weight. On a repeat visit, that means trim balancing: a quick touch-up with no new trial runs — one run to measure, calculate the small added weight, fit it, and one check run. Time on site is noticeably shorter, and the line stays down for less time.

The same principle applies to scheduled checks. If you've built balancing into your maintenance schedule, measuring at the same points, in the same direction and under the same running conditions turns into a trend. A rise relative to your own baseline tells you more than a comparison against an absolute table of limits.

The absolute boundaries of the vibration severity zones depend on the type of machine, its power, and whether the foundation is rigid or flexible. The applicable part and edition of ISO 20816 needs to be checked against the specific machine — there are exceptions. We record the before-and-after figures in the report under identical conditions, rather than fitting the result to a convenient row in a table.

Sources: ISO 20816-1:2016

What we bring to the site

We work with Balanset instruments. That's not an abstract quality promise — it's a specific set of capabilities that determines what we can get done in a visit.

The Balanset-1A kit includes two vibration sensors, a laser phase sensor, a two-channel USB module with preamplifiers, integrators and an ADC, Windows software, and a case. The two channels work simultaneously, so we see both bearing housings at once, not one after the other. The software calculates balancing in one and two planes using the influence-coefficient method, shows the FFT spectrum and the time waveform, and separates overall vibration velocity from the 1x component and its phase.

The practical benefit is in the details. The instrument checks on its own whether the trial weight — a temporary weight whose effect on the rotor's response is used to calculate the correction — was well chosen. It splits the calculated weight across fixed blade or hole positions, and works out material removal by drilling when welding isn't an option. It recalculates weights for other planes and works out the tolerance under the G grades. The data goes into an archive, which the report is later built from.

We also sell the Balanset instruments ourselves: the Balanset-1A costs 1975 EUR + VAT, the OEM version without the case is 1735 EUR + VAT, and we also have our own shop on eBay. The instrument works both for on-site balancing in the machine's own bearings and as a measuring system for soft-bearing balancing machines. The engineers who design and manufacture Balanset also balance with it on site themselves, so the advice you get comes from people who work with their hands, not just from a manual.

Sources: Balanset-1A manufacturer specification · Balanset-1A operation manual

How to arrange a visit

1. 01

   Send us a description of the machine

   Machine type, power or rotor mass, running speed, type of supports and drive, and the site address. That's enough for us to name the package and work out the travel.

2. 02

   Add photos and figures

   Photos of the whole machine, the bearing housings, and the access to the correction plane. If you have vibration readings, send the overall level and the 1x value for each bearing, and what's changed on the machine in the last month.

3. 03

   Get a quote and agree on a window

   We send you the cost of the work, the travel and any extra options before the visit. You tell us the time when the machine can be stopped and started.

4. 04

   We come out and work from the measurement

   An initial measurement, a check of the mechanics, a trial run, calculating and fitting the weight, and a check measurement at the same points and under the same conditions. If it turns out the problem isn't unbalance, you'll hear that on site, not in a report a week later.

Phone and WhatsApp: +351 931 831 229. Email: axilinegeral@gmail.com. Instagram: @axiline.pt. Base: Rua das Colectividades 76 R/C ET, 4430-625 Vila Nova de Gaia. Write to us on WhatsApp if it's easier to send a photo and a short video of the machine running — they show more than a description in words.

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