Optical coating machine: What should buyers know before purchasing?

In the field of optical manufacturing, optical coating machines are the core equipment that determines the performance of products. Whether it is the production of mobile phone lenses, camera lenses, or optical components for aerospace, the quality of the coating directly affects key indicators such as the light transmittance, reflectivity, and wear resistance of the products. However, there are numerous types of optical coating machines with complex technical parameters, and the qualifications of manufacturers in the market vary greatly. Many buyers, due to insufficient preparation in advance, have fallen into predicaments such as "purchasing inferior machines at high prices" and "mismatch between equipment and demand". This article will sort out the key information that buyers must master before purchasing optical coating machines from core dimensions such as technical cognition, demand positioning, manufacturer investigation, and cost accounting, to assist in precise procurement.

Optical coating machines are not "general-purpose equipment". Different coating technologies correspond to different application scenarios, and core parameters directly determine the adaptability of the equipment. Buyers need to first establish a basic understanding of the technology to avoid being misled by the professional terms of manufacturers.

1. Core type: Select the right direction based on the coating principle

   At present, the mainstream optical coating technologies are divided into two major categories: physical vapor deposition (PVD) and chemical vapor deposition (CVD). Among them, PVD technology is the most widely used in the optical field and can be specifically classified into the following three types, with significant differences in their applicable scenarios:

   • Evaporation coating machine:

     It evaporates the coating material through resistance heating, electron beam bombardment and other methods, and condenses it into a film on the surface of optical components. The advantages are good uniformity and high purity of the film layer, which is suitable for coating single or multiple layers of dielectric films (such as anti-reflection films, reflective films), and is widely used in civilian optical products such as spectacle lenses and camera lenses. The drawback is that the adhesion of the film layer is relatively weak, making it unsuitable for scenarios with extremely high wear resistance requirements.

   • Sputtering coating machine:

     It uses plasma to bombard the target material, causing the target material atoms to escape and deposit on the surface of the workpiece. The film layer has strong adhesion and high density, and can be coated with metal film, alloy film and composite film. It is suitable for wear-resistant and scratch-resistant scenarios such as mobile phone camera protection films and automotive glass. However, the deposition rate is relatively slow, and the equipment cost is higher than that of the evaporation coating machine.

   • Ion-assisted coating machine:

     During the evaporation or sputtering coating process, an ion source is introduced to bombshell the film layer, enhancing its density and adhesion. This type of equipment combines the high efficiency of evaporation coating with the high performance of sputtering coating, making it the preferred choice for high-end optical components such as laser lenses and aerospace optical lenses, but it is also the most expensive.

   Buyers need to select the type based on their own product requirements. For instance, for the production of ordinary reading glasses lenses, an evaporation coating machine can meet the needs. If military-grade optical telescope lenses are to be produced, an ion-assisted coating machine is required. If one blindly pursues "high-end technology", it will lead to a waste of equipment investment. If the selected technology fails to meet the product standards, it will lead to production rework.

2. Key Parameters: Focus on the indicators directly related to production

   Parameters are the quantitative manifestation of equipment performance. Buyers should pay close attention to the following six core indicators to avoid falling into the trap of "parameter piling"

   • Vacuum degree:

     It is the foundation of coating quality. The higher the vacuum degree, the fewer impurities and the higher the purity of the coating layer. Civilian optical products usually require a vacuum degree of over 10⁻³Pa, and high-end products need to reach the 10⁻⁵Pa level. It is necessary to pay attention to whether the manufacturer marks "ultimate vacuum degree" or "working vacuum degree", the latter of which can better reflect the actual production status.

   • Coating chamber size:

     Determines the quantity and maximum size of workpieces that can be processed at one time. The selection should be based on one's own production scale (batch size) and workpiece specifications (such as lens diameter, lens module size). For example, when producing 8-inch optical glass, the diameter of the coating chamber should be at least 300mm. At the same time, the arrangement of the workpiece racks should be considered to ensure space utilization.

   • Quantity and type of target material:

     The target material serves as the carrier of the coating material. Multi-target material equipment can achieve the coating of multi-layer composite films. If it is necessary to produce anti-reflection films (usually multilayer dielectric films), equipment with more than three target sites should be selected. The type of target material needs to match the coating material. For example, titanium targets should be used for coating TiO₂ films, and silicon targets for coating SiO₂ films.

   • Deposition rate:

     It directly affects production efficiency and is usually measured in nm/min. The deposition rate of evaporation coating machines is relatively fast (up to 50-100nm/min), while that of sputtering coating machines is slower (5-20nm/min). The buyer needs to strike a balance between the rate and the quality of the film layer in combination with the production cycle requirements.

   • Uniformity of film thickness:

     It is a core indicator of optical components. Uneven film layers can cause fluctuations in the light transmittance of the product. The uniformity error of film thickness for high-quality equipment should be controlled within ±2%. It is necessary to require the manufacturer to provide actual test reports instead of theoretical data.

   • Control system:

     A highly automated control system can reduce manual operation errors and enhance production stability. Give priority to choosing equipment equipped with a PLC control system that supports parameter storage and one-click invocation, especially suitable for the production of multiple batches and multiple specifications of products.

The essence of purchasing an optical coating machine is to "serve production needs". Purchasing that is divorced from one's own scenario will inevitably lead to waste of resources. Buyers need to clearly define their demands from the three dimensions of product, production capacity and cost, and avoid being "overly ambitious and comprehensive" or "excessively cutting costs".

1. Product-oriented: Work backward from terminal standards to meet equipment requirements

   The requirements for coating quality of optical products in different industries vary greatly. Buyers need to first clarify the standards of the terminal products and then work backward to determine the conditions that the equipment must meet:

   • For civilian consumer-grade products (such as eye lenses and mobile phone covers):

     the focus is on the light transmittance of the film layer (usually required to be ≥95%) and wear resistance (pencil hardness ≥3H). The ultimate performance requirements for the equipment are relatively low, and cost-effective evaporation coating machines or basic sputtering coating machines can be selected.

   • Industrial-grade products (such as machine tool optical lenses, inspection instrument lenses):

     It is necessary to take into account the stability of the film layer and environmental resistance (high temperature resistance, moisture resistance). It is recommended to choose an ion-assisted coating machine to ensure that the adhesion of the film layer reaches the 5B level in ASTM D3359 standard.

   • For high-end precision products (such as liDAR lenses and aerospace remote sensing lenses):

     extremely high requirements are placed on the purity, uniformity and stability of the film layer. It is necessary to select high-end equipment with vacuum baking function and multi-ion source configuration, and at the same time, the manufacturer is required to have military-grade production qualifications.

   In addition, if the product specifications to be produced are diverse (such as lenses of different diameters and optical components of different shapes), equipment with adjustable workpiece racks and support for quick target changing should be selected to reduce production change time.

2. Capacity planning: Match the current scale with future growth

   The production capacity of the equipment should be matched with its own production scale, while reserving a certain growth space to avoid the situation of "a small horse pulling a big cart" or "a large horse pulling a small cart".

   • For start-ups or small-scale production:

     Enterprises with an annual output of less than 1 million pieces are recommended to choose single-chamber small coating machines (coating chamber diameter ≤400mm). This type of equipment occupies a small area (usually ≤5 square meters), has a low investment cost, and can quickly achieve production start-up.

   • Medium-sized enterprises:

     For those with an annual output of 1 to 5 million pieces, they can choose double-chamber or multi-chamber continuous coating machines to achieve a "feeding - coating - discharging" assembly line operation, enhancing production efficiency and reducing the waiting time for vacuum pumping.

   • Large-scale mass production enterprises:

     Enterprises with an annual output exceeding 5 million pieces need to customize production lines, equipped with automatic loading and unloading systems and online film thickness detection devices, to achieve full-process automation, reduce labor costs, and ensure the consistency of batch production.

3. Cost budgeting: Balancing initial investment and long-term operation

   The procurement cost of optical coating machines ranges from several hundred thousand to tens of millions. Buyers need to establish a "full life cycle cost" mindset rather than merely focusing on equipment quotations.

   • Upfront investment:

     including the price of the equipment itself, installation and commissioning fees, and site renovation fees (such as vacuum pipeline laying, anti-static floor treatment). Some high-end equipment needs to be equipped with dedicated cooling systems, and the cost of this part also needs to be included in the budget.

   • Operating costs:

     Mainly include target material consumption (accounting for 30%-50% of operating costs), electricity charges, vacuum pump oil replacement costs, and labor costs. For instance, the target material utilization rate of sputtering coating machines is lower than that of evaporation coating machines, and the long-term operating costs are higher. Therefore, a comprehensive consideration should be made in combination with product profits.

   • Maintenance cost:

     The service life of core components of the equipment (such as vacuum pumps and ion sources) is usually 3 to 5 years. It is necessary to understand the replacement cost and cycle in advance to avoid the problem of "difficult maintenance and high cost" in the later stage.

The technical threshold for optical coating machines is high, and the strength of the manufacturer directly determines the quality of the equipment and the subsequent service guarantee. Buyers should avoid "small workshop-style" manufacturers and strictly screen from the following three dimensions:

1. Qualification Certification: A "hard indicator" for verifying technical strength

   A legitimate manufacturer should have complete qualification certifications, which is the fundamental guarantee of equipment quality.

   • Production qualifications:

     Must possess the "Special Equipment Manufacturing License" (vacuum equipment is classified as special equipment) and ISO9001 quality management system certification to ensure standardized production processes.

   • Technical Certification:

     If it involves high-end applications (such as military or medical), the manufacturer must possess the corresponding industry certification (such as the military product quality system Certification GJB9001C). If the core components (such as vacuum pumps and ion sources) are imported, the original import certificate and customs declaration form must be provided.

   • Patent technology:

     Manufacturers with independent patents (such as patents for film thickness control systems and vacuum sealing technology) usually have stronger technical capabilities and can avoid purchasing "counterfeit equipment".

2. Service Capacity: The "soft power" ensuring the stable operation of equipment

   The installation, commissioning and maintenance of optical coating machines have extremely high technical requirements. The service capabilities of manufacturers directly affect the production efficiency and service life of the equipment.

   • Installation and commissioning:

     The manufacturer is required to provide on-site installation and commissioning services, clearly define the commissioning period (usually 1-2 weeks), and ensure that all parameters of the equipment meet the standards stipulated in the contract after commissioning (such as uniformity of film thickness and vacuum degree).

   • Personnel training:

     It should cover equipment operation, daily maintenance, troubleshooting of common faults, etc., to ensure that enterprise employees can operate the equipment independently and avoid equipment damage caused by improper operation.

   • After-sales response:

     Clearly define the after-sales response time (such as remote guidance within 2 hours and on-site service within 24 hours), especially for core production equipment, where downtime leads to significant losses. A rapid after-sales response is of vital importance. At the same time, find out whether the manufacturer has service outlets and spare parts warehouses in the local area to avoid delays in spare parts supply.

3. Case Verification: Refer to the "real feedback" from peers

   The cases of manufacturers are the most direct proof of their strength. Buyers need to pay close attention to:

   • Peer cases:

     Give priority to choosing manufacturers that have served leading enterprises in the same industry, such as those that produce mobile phone lenses. You can examine whether the manufacturer is a supplier to companies like Huawei and Xiaomi. Such manufacturers have a better understanding of industry demands and their equipment is more compatible.

   • Case authenticity:

     It is required that manufacturers provide customer contact information, conduct on-site visits or phone conversations to understand the actual operation of the equipment (such as failure rate, production efficiency, and stability of film layer quality), and avoid being misled by "false cases".

   • Long-term cooperation situation:

     If the cooperation between the manufacturer and the customer exceeds 3 years and there are secondary purchases, it indicates that the quality of the equipment and service have been recognized and are trustworthy.

After determining the manufacturer, the contract signing and trial operation stages are the last line of defense to avoid risks. Buyers should pay close attention to the following details to prevent subsequent disputes:

1. Contract terms: Clearly define rights, responsibilities and acceptance criteria

   The contract should detail the equipment parameters, acceptance criteria, payment methods, after-sales guarantees and other contents to avoid vague expressions.

   • Parameter details:

     Clearly include core parameters such as vacuum degree, film thickness uniformity, and deposition rate in the contract, and indicate specific values and detection methods (such as which brand of film thickness gauge to use for detection).

   • Acceptance criteria:

     Two stages, namely "no-load acceptance" and "load acceptance", are agreed upon. No-load acceptance checks whether the parameters of the equipment itself meet the standards. The load acceptance shall be conducted by coating tests on the actual workpieces of the buyer to ensure that the product quality meets the terminal standards (such as light transmittance and wear resistance), and the acceptance report shall be signed and confirmed by both parties.

   • Payment Method:

     It is recommended to adopt the "3-4-2-1" payment model, that is, 30% of the advance payment is made after the contract is signed, 40% is paid after the equipment is installed and debugged at the factory, 20% is paid after the acceptance is qualified, and 10% is paid after the warranty period expires, to reduce the payment risk.

   • Warranty terms:

     Clearly define the warranty period (usually 1-2 years). Within the warranty period, core components (such as vacuum pumps and ion sources) must be replaced free of charge, and specify the criteria for distinguishing between human-induced damage and normal wear and tear.

2. Trial operation stage: On-site testing of equipment performance

   The trial operation is a crucial step to verify the quality of the equipment. The buyer needs to participate throughout the process and focus on testing the following contents:

   • Stability test:

     Run the equipment continuously for 72 hours to observe whether the vacuum degree is stable, whether the uniformity of the film thickness fluctuates, and whether there are any faults in the control system.

   • Efficiency test:

     According to the normal production process, calculate the time for a single coating (including vacuuming, coating, and venting) to verify whether the production efficiency of the equipment meets the manufacturer's commitment.

   • Product testing:

     Performance tests are conducted on the workpieces coated with equipment, such as measuring the light transmittance with a spectrophotometer and the hardness of the film layer with a wear resistance tester to ensure that the products meet the production requirements.

Purchasing an optical coating machine is a systematic project involving technology, cost and service. Buyers need to abandon the purchasing mindset of "only looking at the price" and "blindly following the trend", and be well-prepared throughout the entire process from "technology cognition - demand positioning - manufacturer screening - risk avoidance". Only by precisely matching the performance of the equipment with production demands and choosing a manufacturer with strong capabilities can the optical coating machine become the "core engine" for enhancing product competitiveness, rather than a "burden" for later operation. Under the major trend of intelligent manufacturing, high-quality optical coating equipment not only ensures stable production but also provides solid technical support for enterprises to cope with market competition.