Fixed-Weight Navel Orange Packing Line with In-Line Carton Forming

The industry's first integrated system solution for fixed-weight fruit packing: carton forming, linear multi-head combination weighing and case sealing at 25 cases per minute.

Client A navel orange packing operation in Jiangxi, China
Fresh Produce and Agriculture
Region Jiangxi, China

Request a Quote for a Similar Project Chat on WhatsApp

Client Background

Navel oranges are sold by weight, not by count. A carton has to contain a declared net weight, and fruit arriving from the grading line varies in size, so a fixed number of pieces per carton does not produce a fixed weight. A packing house therefore needs a weighing step that can hit a target net weight with fruit of varying size, and then a carton forming step and a sealing step that keep up with it. At the time of this project there was no packaged system solution for this application in the industry — the three steps were normally bought separately and integrated on site. This project delivered them as one line: in-line carton forming, a linear multi-head combination weigher, and case sealing, running at 25 cases per minute across six carton formats used through the season. The same line class also produces load-bearing display cartons, in which the three-piece carton base carries the fruit on the retail shelf — a format that requires the carton itself to hold stacking load rather than the shipper case.

Challenges

Fixed weight rather than fixed count

Fruit is sold by declared net weight. Because fruit size varies coming off the grading line, the line has to weigh and combine rather than count — which is why the specification centres on a linear multi-head combination weigher instead of a counting system.

Fruit must not be dropped hard

Every transfer — from the weigher into the formed carton in particular — has to be a controlled drop. A hard drop produces bruising that is not visible on the packing line but shows up days later in the customer's store, and the damage is attributed to the fruit, not to the handling.

No existing system solution to build on

There was no packaged system solution for this application in the industry at the time of the project. Carton forming, combination weighing and case sealing had to be integrated from scratch as one controlled line, including the interfaces between them.

Six carton formats through the season

Six carton formats are used as the season progresses and fruit sizes change. Changeover has to be done by the packing house's own staff within a 25-minute window, so it must not depend on ZRAY being on site.

How ZRAY Solves It

The line was designed as one controlled sequence because the three steps fail each other if they are bought separately. **In-line carton forming machine.** The carton is formed at the head of the line so the weigher always discharges into a carton that is already square and ready. Forming in line removes the manual carton handling that would otherwise sit between weighing and sealing. **Linear multi-head combination weigher.** Combination weighing is what makes fixed weight achievable with fruit of varying size: the weigher selects the combination of portions closest to the target net weight rather than filling a fixed number of pieces. Discharge into the carton is a controlled drop height, which protects against the bruising that only appears downstream. **Case sealing machine.** Sealing closes the carton behind the weigher. Weight data feeds back to the control layer so an out-of-tolerance carton is rejected rather than shipped. **Six formats with a 25-minute changeover.** Carton formats are stored as recipes with the mechanical references called out in the HMI. Changeover is a format selection plus the reference positions, which the packing house's own staff can perform in the changeover window. **Display cartons and load-bearing bases.** The line class also covers the three-piece load-bearing display carton, where the carton base carries the fruit on the retail shelf. That format requires the forming step to hold base strength and stacking load, not only to close a box. **Why it matters.** This was the industry's first integrated system solution for fixed-weight fruit packing. The value is not only the 25 cases per minute — it is that forming, weighing and sealing are one line with one control and one changeover procedure, instead of three machines from three suppliers integrated on site.

Single-Piece Carton & Case Erector Machine

Up to 35 Trays/Min |

View Details

In-line carton forming machine Forms the carton at the head of the line so the weigher always discharges into a ready carton.

Linear multi-head combination weigher Selects the portion combination closest to the target net weight with fruit of varying size.

Case sealing machine Closes the carton behind the weigher, with weight data fed back for rejection control.

Weight feedback and rejection control Out-of-tolerance cartons are rejected instead of shipped.

Six-format changeover kit Recipe plus mechanical references; 25-minute changeover by the packer's own staff.

Three-piece display carton capability Load-bearing carton base for retail display, formed in the same line class.

Project Results

25 cpm

Carton output

6 formats

Carton formats used through the season

25 min

Format changeover time

1 line

Forming, weighing and sealing integrated as one system

Project Timeline

01

Fruit and packing survey

Fruit size range, target net weights and the six carton formats reviewed; weighing strategy chosen against real fruit rather than a nominal specification.
02

System design and build

Carton forming, combination weighing and sealing engineered as one line, including the transfer that controls the drop into the carton.
03

Factory run and FAT

Line run on representative fruit at the ZRAY plant, including changeover between formats.
04

Season-start installation and training

Line installed and commissioned ahead of the season; the packing house's own staff trained on all six format recipes.