Have you noticed a quality shift in the weighing industry? Quality standards have decreased significantly on consumer scales with “assembly only” operations making big waves in the scale community. Large sellers are dominating the online retail space for consumers, and this is not any different for scales. Whether you support the unstoppable rise of these ecommerce giants or not, there is no denying the profound impact associated with their operation.

We bought some of the “Best Selling”, highly rated, affordable scales and balances to test the quality. Yes, with 2-day free shipping too. Our discoveries were astounding. At first glance we found non-UL approved AC adapters and direct wall plugs into scales with- out UL. As we all know, overheating or short circuitry can cause electrical shocks and fires. UL adapters are built by larger transformer companies and cost twice as compared to non-UL parts. We reached out to UL Solutions headquarters specifically and were surprised to hear that electrical products sold in the US do not need to bear a UL marker legally.

What prompted this experiment?

The amount of recent new brands in the US market. We managed to trace back all the way to the manufacturers in China, who, surprise, are not scale manufac- turers. Upon further investigation Online Sellers approached these electronic companies and offered to help sell their products direct to end-users through fulfillment centers across the US. The number of units sold are between 300,000 to 500,000 over the last few years.

These new companies outsourced everything from blank scale casings, load cells, displays, cables, adapters, display PCBAs and even arranged for independent software engineers to change price computing scales’ software to counting scale software. This technique has proven successful for these operations. However, at what cost to the consumer? Let’s dissect below.

First up, product evaluation.

Scales we purchased:

• Counting Scale 30kg x 1g – $140, 30,000 division scale. Typical per- forming 6,000 division, 30kg x 5g balance sells for $200 – $900 depending on features. Note the 6,000 divisions specification.
• 500g x 0.001g – $128, 500,000 division scale. Scales of this cali- ber would generally be called precision balances and would sell for several thousand dollars each but would also have tight accuracy specifications and be appropriate for actual laboratory usage.
• Balance 3000g x 0.01g – $105, 30,000 division scale.
• Shipping Scale 440lb x 0.05lb – $42, 8,800 division scale.
• Shipping Scale 440lb x 6 oz – $39, 1,173 division scale.
• NTEP price computing scale – $49. Compare to a local dealer’s pricing that generally includes install, warranty and certification at $300+.

1. Non-UL approved AC adapters & direct wall plug into scale without UL

Low quality AC adapters can overheat, and bad circuitry can cause electrical shocks and fires. UL adapters are built by larger companies, have circuitry to prevent overheating. And yes, they do cost twice compared to non-UL parts.

Non-UL approved AC adapters.   A step-down non approved transformer inside a scale.

Many new brands selling direct in the US market do not have a US company presence here, hence their products may not have product liability insurance in the event that these AC adapters and step-down transformers start a fire or cause electrical shocks.

2.  AD Processor (Analog to digital signal converter)

In full transparency, our industry standard is that most repu- table balance companies only use high quality US made Analog to Digital converters on high resolutions weighing devices like bal- ances & counting scales. In contrast, low-cost manufacturers use kitchen scale A to Ds to reduce cost. Kitchen scale processors are

$0.10 to $0.28 only High-end A to Ds have precision resistors in the expanded electronics, faster speed and much less front-end electrical noise, costing $7-12 range.

Left and middle show kitchen scale electronics. Right shows balance electronics.

3.  Masking Software

This is a software trick to deceive users and consumers that the balance is accurate. For an example, when the scale does not return to ZERO, and there are still -/+ readings, the software will allow the scale to display ZERO. All scales have zero tracking software, if this is increased to a wider window (d or divisions), the perception is that the “zero” is good.

Linearity errors from less accurate load cells can be corrected by 3-point, 5-point linearity adjustment software. This is generally acceptable on older scales where material counterforce is worn over many cycles, except that it does not correct hysteresis and repeat- ability errors. Software can also be written to repeat weights like 100.00g, 200.00g, 500.00g.

The standard in the weighing industry is to place or take out 1.5d to 2d on the balance, and it should show at least 1d change in weight. If the scale shows weight jumps like 100.00 to 100.04 to 100.7 to

101.00 then it is most likely the AD, load cell and software are not sensitive enough to be considered as 0.01g balance.

One can use lower cost 3000g x 0.1g balance and market as 0.01g. Place a 0.1g test weight on the balance, and it will still register as 0.00g. The zero tracking or AZM is set very wide, so the scale is dull and non-sensitive. Another way is to place 100.00g weight, it showed 100.00g. Now place 100.01g weight and then 100.02g and 100.03g weights. Lower cost balances will not be able to detect these minute changes.

4.  Load Cells

A 3000g load cell can cost $1, $4 to $20 and look exactly the same. There are accuracy differences between kitchen grade, 30,000 division and 300,000 division load cells. There are many sensor companies making $1 kitchen scale load cells in China, few have the technical knowhow to make 30,000 divisions and less than 3 sensor manufacturers can make 300,000 divisions sensors. They cost a lot more because of the know-how, material and time needed to test the cells to meet specs.

The 440lb x 0.05lb (8,800 External divisions!) The shipping scale uses bathroom scale electronics (right photo) and no AD processsor. These are 1000-ohm single gage metal load beams, about $1 for set of 4. These are very inaccurate, and no corner adjustments are made, meaning that the scale may give different weight readings at all for 4 corners.

Regular industrial grade load cell costs $6-12 for set of 4. They have temperature compensation and corners are adjusted.

Left shows a single point aluminum load cell. Middle and right show bathroom scale metal single gage load cells with no temperature compensation used in low- cost shipping scales.

5.  Temperature Compensation

Low-cost load cells are mass temperature compensated, meaning that for every 10,000 pieces, the factory only check a few units and compensate the entire batch with the same resistors. They are used in kitchen and bathroom scales.

On the above right photo, these are single gage metal tab load cell without any temperature compensation.

High end load cells are individually temperature compensated used in bench scales, balances and counting scales.

It matters only if your product’s weight might differ from morning to afternoon because of temperature changes in the warehouse.

6. Corner Adjustments

Corner adjustments and corner tests take a lot of time to adjust by filing down the material or adding resistors. Most of the low-cost scales skip this assembly process to save labor hours.

7. Overload and Side Load Stops

No overload or side load protection on the scales as this takes more assembly time and parts. The weighing scale is much more susceptible to damage.

Top left shows load cell mount with overload and side load protections. The other two photos show no overload and side load stops. Also, load cells are mounted directly on plastic or just a thin strip of stamped metal instead of a large rigid metal plate.

8.  Wrong Capacity Load Cells

Our industry standard is that we use 1.5 to 2 times the load cell capacity to scale capacity. 1.5 times is acceptable in balances and counting scales because there no shock loadings, and 2X is used in other heavier industrial weighing scales.

Below is a 3000g load cell used in a 3000.00g balance. Assum- ing the platter and sub-structure weigh 400g, the usable capacity is only 2600g.

When a 3000g weight is placed on the balance, the initial weight can be as high as 4000g, so having a remainder capacity of 2600g is insufficient to avoid overloading the load cell.

The reason why a smaller capacity load cell is used in lower cost balances is that it does not have sufficient internal resolutions/counts to display the weight.

A 3000g load cell being used in a 3000g balance.

9. Load Cell Mounts

Without any temperature compensation.

High end load cells are individually temperature compensated used in bench scales, balances and counting scales.

Load cells are mounted on plastic instead of a steel plate. This is incorrect as plastics do flex and bend over time. It is the same as plastic footing (plastic threads).

The mount on the top of the load cell (below, left) is made from thin steel and there is no bottom support for the load cell that rests on plastic scale base. Best material a thick steel plate or diecast steel or aluminum and on the top of the load cell. This is also why the top scale brands are, literally, twice as heavy

A price computing scale casing and load cells are either mounted directly on a plastic base or on a thin strip of pressed steel.

10. Plastic Draft Shield

Ever notice that all high-end balances only use glass draft shields. Plastic draft shields create static, so if you are weighing 0.01 or 0.001g, the static on our clothing and hands can cause significant errors when transferred to the draft shields.

Left shows plastic draft shield and right shows glass draft shield. Yes, heavier and more expensive to ship, but you get more accurate weights without static.

11. Casing

Recycled plastics are much less expensive than new ABS plastics, but recycled plastics do crack easily. Low- cost price computing scales with pricing calculations, sell for $10, that include load cell, display, keypad, AC adapter, casing, AD processor, and all electronics. Manufacturers changed the software and are selling them as counting scales in the US market. Photos show low-cost price computing scale casing and mounting design

Left and middle show price computing scale housing used in high resolution counting scales. Right shows plastic footing with plastic threads on the footing to the left.

12. Fake NTEP

The NTEP #COC (Certificate of Conformance) is real except sellers used same #COC meant for one type of scales on others with differ- ent mounting designs. OEM manufacturers also switched out NTEP load cells to other non-NTEP brands to save costs.

If there are interests in this article, let the writer know. We can go into more details on the product’s internal designs and costing and we have started making videos showing the differences. Most importantly, please buy genuine quality products from established brands and through reputable distributors.

I have been in the weighing industry since 1987, worked in international marketing, manufacturing, product engineering & designs in Ohio, Hong Kong, Singapore, Malaysia, Thailand, China, and Spain and in the last 15 years in Northern California.

Here are a few suggestions and take-aways related to buying scales online:

If your application is not “critical” I would suggest that kitchen, bathroom and even mail and parcel scales are not “critical” and can use the less expensive scale designs.

If you have applications like counting and your parts or pieces are of high value – you owe it to your business to invest in reliable and accurate equipment. You will also want to invest in a local scale provider so that your equipment can be well maintained and accurate.

If your application involves selling, you need to invest again in a reliable piece of equipment with local service available. If you are buying a grocery item do you expect accurate weights? Of course you do, so selling on a discount, non-certified scale without local inspec- tion is first, illegal and second, just wrong.

If your application is high volume freight, again you owe it to your business to make a good investment as quality scales will likely save your company money. And just to note, both UPS and FedEx have no trouble charging back wrong freight charges – that costs you extra and you can’t charge that freight to your customer as you have already billed them.

That saying, “You get what you pay for” is explicitly valid in this circumstance. Kitchen scales and low-end shipping scales have their place, but that is not in valid business applications where quality is required. I would encourage you to take special care when making decisions about weighing equipment!