In packaging machinery (such as filling machines, labeling machines, sealing machines, packaging lines, etc.), the linear guide needs to meet the high-speed reciprocating, high-frequency start and stop, accurate positioning, anti-pollution and other core requirements. Select the appropriate linear guide, need to combine the characteristics of the working conditions of packaging machinery, from the "load fit, precision control, environmental tolerance, operational stability" and other dimensions of the comprehensive consideration, the specific methods are as follows:
First, clarify the core working condition parameters: load, speed and stroke
Packaging machinery action is mostly "intermittent reciprocating motion" (such as filling head lift, labeling head translation) or "continuous conveying motion" (such as conveyor belt synchronous guidance), you need to first clarify the following parameters:
1. Load characteristics: Load carrying capacity of the matching guide
Rated and peak loads: The loads of packaging machinery include the self-weight of the components (e.g. slider + actuator, e.g. barrels of a filling machine) and the working loads (e.g. pressure during filling, compression force during labeling). It is necessary to calculate the "actual load" (usually take the peak load, such as the inertial load at the moment of starting and stopping), and to ensure that the rated dynamic load of the guideway (C) ≥ the actual load × safety factor (1.2-1.5).
Example: a labeling machine labeling head weight 50kg, labeling pressure 100N, the peak load of about 600N (including inertia), you need to choose the rated dynamic load ≥ 720N guide rail (such as HGR15 C value of about 1050N, can meet).
Load direction: the load of packaging machinery is mostly in the vertical direction (such as lifting) or horizontal direction (such as translation), it is necessary to choose a guide that can withstand multi-directional loads (such as the four-row arc raceway structure, which can withstand radial, axial and tilting moments, and is suitable for complex force scenarios).
2. speed and acceleration: to avoid dynamic failure
Linear speed: high-speed packaging machine (such as instant noodle packaging machine) slider line speed up to 3-5m / s, need to ensure that the guide DN value (ball diameter × speed) or line speed in the permissible range (most of the rolling guide line speed upper limit of 10m / s, more than the friction is easy to heat up and lead to lubrication failure).
Acceleration: start-stop frequent equipment (such as 30 times per minute reciprocating sealing machine) acceleration of up to 5-10m / s ², the need for high rigidity guide (to avoid deformation), otherwise easy to produce "resonance" resulting in positioning errors (such as sealing position offset ± 0.5mm). 3.
3. Stroke length: adaptable mechanical structure
short stroke (such as filling head lift stroke 50-200mm) can choose a single guide rail; long stroke (such as assembly line guide stroke 2-5m) need to consider the guide rail splicing (need to ensure that the parallelism at the splicing ≤ 0.1mm/m), or choose to support long stroke customized models.
Second, according to the precision needs to choose the accuracy level
positioning accuracy of packaging machinery directly determines the product qualification rate (such as labeling offset > 0.5mm is considered unqualified), the need to match the accuracy level of the guide rail:
| Accuracy class (common) | Straightness(1000mm) | Parallelism (double-track mounting) | Applicable scenarios |
| Class C (Normal) | ≤0.15mm | ≤0.2mm/m | Low-precision scenarios (e.g., ordinary case sealers) |
| Class H (High Precision) | ≤0.05mm | ≤0.1mm/m | Medium-precision scenarios (e.g. fillers) |
| P-class (precision grade) | ≤0.02mm | ≤0.05mm/m | High-precision scenarios (e.g. high-speed labelers) |
Example: high-speed labeling machines need to control the label positioning error within ± 0.1mm, you need to choose H level and above precision guideway (such as HGR20-H level), with the closed-loop control of the scale, to meet the needs.
Third, to adapt to the special environment of packaging machinery: anti-pollution and protection
packaging machinery working environment is diverse (dust, moisture, corrosive media, etc.), the guideway needs to have targeted protection capabilities:
1. anti-dust and anti-pollution: to avoid stagnation and wear
dust environment (such as powder packaging machines, granule packaging machines): choose the slider with double sealing + scraping plate (such as HGR series of "end sealing + side sealing" structure), scraping plate can block the powder into the raceway (particle size > 5μm dust interception rate of ≥ 95%), to avoid the ball Stuck.
Humid / water vapor environment (such as beverage filling machine, wet wipes packaging machine): the surface of the guide rail should be rust-proof treatment (such as chrome layer thickness ≥ 10μm), the slider sealing ring adopts water-resistant rubber (such as nitrile rubber), to prevent water vapor from seeping into the raceway, resulting in corrosion.
Corrosive environments (such as chemical packaging machine): stainless steel rail (material 304 or 316), ball using ceramic material (corrosion-resistant and non-magnetic), to avoid chemical media erosion of metal surfaces.
Fourth, the structure of adaptation and ease of installation
packaging machinery space is compact (such as small pillow packaging machine), the structure of the guide rail needs to match the layout of the equipment:
Size specification: according to the installation space to choose the width of the guide rail (such as HGR15 width 15mm, suitable for small equipment; HGR30 width 30mm, suitable for larger loads of the assembly line), to avoid structural interference due to the size is too large.
Slider type: Flange type slider (e.g. HGR-F type) is suitable for top mounting (e.g. labeling head fixing), square type slider (e.g. HGR-S type) is suitable for side mounting (e.g. conveyor belt guiding), which needs to be selected according to the mounting holes of the equipment and the direction of force.
Installation compatibility: The guide rail needs to support "fine-tuning installation" (e.g. adjusting the parallelism through the side waist-shaped holes) to reduce the difficulty of assembly. For example, in parallel installation of double rails, the parallelism can be detected by a percentage meter (error ≤ 0.05mm/m) to ensure smooth operation.
Five. Operation Stability and Maintenance Costs
Packaging machinery needs to run continuously for a long time (e.g., 16 hours per day), the "low failure and easy maintenance" characteristics of the guide rail are crucial:
Wear resistance and life: choose high hardness guide rail (slide HRC58-62, ball HRC60-65), with long-lasting grease (e.g. lithium-based grease, filling cycle ≥ 300 hours), to extend the service life. For example, the life of HGR series can reach more than 1000km (about 20,000 hours of operation) under the working condition of 500N load and 1m/s speed.
Low noise and smoothness: the rolling friction coefficient (0.001-0.003) is much lower than that of sliding guide (0.1-0.3), and the running noise is ≤65dB (in line with the workshop noise standard), which avoids vibration leading to packaging material deflection (e.g., film run-off).
Maintenance convenience: the slider needs to be designed with "easy oiling holes", which can be supplemented with lubrication without disassembling; the surface of the guide rail is smooth (Ra ≤ 0.8μm), which reduces dust adherence and lowers the cleaning frequency.
sixth, cost and brand selection
Initial cost: well-known brands (such as HIWIN HGR series) precision stability but higher prices, suitable for high-precision equipment (such as pharmaceutical packaging machines); domestic high-quality guide (such as PMI) cost-effective, suitable for general-purpose packaging scenarios (such as carton sealing machine).
Long-term cost: need to synthesize life, maintenance frequency calculation "unit time cost". For example, the price of a domestic guide for imported 1/2, but the life is only 1/3, long-term use but more expensive.+
Summarize: Selection process
Define load (including peak), speed, travel → match guideway specification (e.g. HGR15/20/30);
According to the positioning accuracy requirement → select accuracy grade (C/H/P);
Analyze environment (dust / vapor / corrosion) → determine protection scheme (sealing / rust / material);
Combine with mounting space and structure → select slider type and size;
Evaluate life span and maintenance costs → Balance brand and budget.
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