6 Things You Should Consider Before Buying a Production Line for Biscuits, Cookies and Crackers

1. Specification of the equipment

The initial task for the Buyer is to define the products to be made and the output (kg/h) to be produced. The control and safety systems can be specified as PLC with HMI or hard wired panels. Other important initial considerations are the factory space and services available, including fuel gas/oil, electricity, compressed air.

The specification should cover considerable detail based on the Buyer’s requirements. The following is an example of a specification for a small snack cracker and semi-sweet biscuit line.

FIG: 1 Overview of Biscuit Production Line

2. Specification for a production line for 750-1000kg/h

Snack cracker

Production output

2.1. MIXING AND DOUGH FEEDING

2.1.1 One – Horizontal mixer, batch capacity 500 - 500kg

FIG 2: Baker Perkins High Speed Mixer

• Stainless steel bowl with water jacket
• Temperature probe for dough temperature
• Direct discharge with 150 degree bowl tilt
• 2 speed or variable speed drive (30/60rpm)
• Ingredient feed ports for 2 dry and 2 liquid ingredients
• Safety guards and lock for dough tub
• Control for mixing times, speeds and dough temperature

2.1.2 Four – dough tubs with castors

2.1.3 One – Dough Feed Unit

FIG 3. Dough tub lift and tilt

• Tub lift and tilt
• Live bottom hopper with guillotine
• Inclined web to feed dough pieces to the hopper of the 3 roll sheeter
• Metal detector with reject system

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2.2. BISCUIT CUTTING MACHINE

Dough sheet width 1200mm

FIG 4: Biscuit cutting machine from Dingson Food Machinery, China

2.2.1  One – 3 roll sheeter, roll diameters 420 – 300mm

• Variable speed drives for forcing roll and gauging rolls
• Dough scrap incorporation at the back of the sheeter hopper
• Delivery web width 1250mm, synthetic material
• Automatic tension and tracking
• Speeds and roll  gaps set by machine mounted HMI

2.2.2  Two – Gauge roll units

• Rolls 300mm diameter
• Adjustable roll scrapers
• Delivery web with automatic tension and tracking
• Web width 1250mm
• Speeds and roll  gaps set by machine mounted HMI

2.2.3  One – Heavy Duty Gauge roll unit

• Rolls 400mm diameter
• Gauging gap 0-8mm
• Delivery web with automatic tension and tracking
• Web width 1250mm
• Nosepiece transfer to intermediate web
• Speeds and roll  gaps set by machine mounted HMI

2.2.4  One - Intermediate conveyor, approx. 2.0m long

• Conveyor web with automatic tension and tracking
• Web width 1250mm
• Speeds and roll  gaps set by machine mounted HMI

2.2.5  One - Rotary cutting machine

• Suitable for separate printing and cutting rolls 200-300mm diameter
• Cutting conveyor web with automatic tension and tracking
• Web width 1250mm
• Speeds set by machine mounted HMI
• Two rubber covered rolls below cutting conveyor to support the printing and cutting operations
• Servo motor control of phasing between printing and cutting rolls
• Printing and cutting roll pressures adjustable
• Dough by-pass facility
• One printing and one cutting roll with plastic inserts for snack cracker

2.2.6  One transfer conveyor

• Conveyor web with automatic tension and tracking
• Web width 1250mm
• Speeds and roll  gaps set by machine mounted HMI

2.2.7  One scrap lift and return system

• Conveyor to pick up dough scrap with adjustable nosepiece at feed end
• Conveyor web with automatic tension and tracking
• Dough scrap cutter
• Cross scrap conveyor
• Side scrap conveyor 300mm wide to deliver the dough scrap to the 3 roll sheeter
• Reciprocating delivery conveyor above the sheeter hopper to deliver the scrap dough evenly across the width of the hopper

2.2.8  Four – ambient air blowers with fixed speed

2.2.9  One - Salt sprinkler with recovery

• Stainless steel hopper
• Variable speed sprinkler roll for salt with brush
• Wire mesh recovery conveyor
• Hopper to collect excess salt and deliver to side of the machine

2.2.10  One – Swivel panner

• Conveyor web with automatic tension and tracking
• Web width 1250mm
• Speeds and roll gaps set by machine mounted HMI
• Unit supported on pivot. Panner will swivel to follow oven band tracking movement guided by rollers which engage the sides of the oven band
• Facility to lift conveyor web clear of oven band

2.2.11  Control system for biscuit cutting machine

• Cascade speed control by PLC
• Operator adjustment by HMI. Roll gaps adjusted by servo motors with setting by HMI

Equipement products

2.3. Direct Gas Fired Baking Oven

• Baking chamber 50m long. Band width 1200mm
• 4 zones: 10.0, 12.0, 14.0, 14.0m
• Band pre-heat burners

Fig: 5  Baker Pacific Direct Gas Fired Oven

2.3.1 Oven feed end

• 1200mm diameter drum with scraper
• Band tracking detection and pneumatic tracking system
• Pneumatic oven band tension system
• Oven band tension monitor
• 3.0m drum centre to baking chamber

2.3.2 Direct Gas Fired baking chamber, 50m long

• 4 zones with separate heat and humidity control
• Expansion joints between each zone
• Explosion relief panels in oven top
• Inspection window in each zone
• Clean out doors in non-control side, approximately 3.0m apart

2.3.3  Burner system

• Fuel: LPG
• Maximum heat rating:  2000kWh (33.3 kWh/m² of oven band)

2.3.4  Gas train

• Manual shut off valve
• Two automatic shut off valves for safety system
• Gas filter
• Zero gas pressure governor
• Gas pressure high/low detection
• Gas pressure gauges at inlet and outlet of gas train
• Gas valve tightness proving system (to check for leakage of gas)
• Main gas pipes and distribution system

2.3.5   Combustion air supply

• 8 – Centrifugal blowers with 2.2kW direct drives
• 8 – Air pressure gauges
• 8 -  Motorised butterfly valves for top and bottom air pressure
• 8-  Pressure switches
• Braided air hoses between air header pipes and burners

Note: The air pressure may alternatively be controlled by variable speed blowers or by motorised valves

2.3.6  Burner system

• 106  – burners with 1200mm strips (18 with multi lane control) includes 6 pre-heat burners
• Turndown ratio: 4/5:1
• Strip design and material: stainless steel corrugated strips
• 106 – Flame managers
• 106 – gas / air mixers with gas / air ratio adjustment
• 106 – solenoid valves
• 106 - gas tube bends

2.3.7  Ignition system

• 106 – electrode shields
• 106 – tube igniters
• 106 – mounting brackets
• 106 – Rajah connectors
• ignition cable

2.3.8  Automatic temperature control

• Four thermocouples are installed in each oven zone to detect the baking temperatures. These provide signals to controllers at the zone control panels / PLC to provide temperature setting and monitoring with digital readouts
• The combustion air pressure is modulated to maintain the set baking temperatures
• The top and bottom burners in each zone are separately controlled

2.3.9  Extraction fans

• Four (4) - Multi-vane Forward Curved Fans
• Volume: 34m³/min
• Pressure: 70mm WG at 20 degrees C 
• Four (4) – Pressure switches for extraction fans

2.3.10  Turbulence / convection system for 3 zones

• Turbulence fan (fixed speed) to distribute convective air to ducts above and below the oven band
• Turbulence ducts adjacent to return ducts to use heat from the return airflow to the burner 
• Even distribution of turbulence from full width ducts running the length of the zones
• Adjustment for top and bottom airflow

2.3.11  Over temperature safety system

• 1 – thermocouple to be mounted in the extraction flue in each zone
• 1 - Omron temperature controller to detect over temperature and actuate main gas shut off valve

2.3.12  Oven delivery end and drive unit

• 1000mm drum unit
• 4000mm extension from drum centre to baking chamber
• Baking time adjustable 3 - 9 minutes by variable speed AC motor with inverter control
• Adjustable stripper knife
• Wire mesh band stripping conveyor with adjustable discharge height and retractable nosepiece for biscuit reject
• Cross scrap conveyor for reject biscuits

2.3.13   Stand by DC drive or standby generator for baking band

• In the event of a failure of the factory power supply. The drive will operate the oven band, stripping conveyor.

2.3.14  Extraction hood

• A stainless steel hood 2000mm long with an extraction fan mounted over the delivery end extension

2.3.15   Oven band cleaner

• Top wire brush to clean inside of the oven band with fixed speed drive.
• Bottom wire brush unit to clean the outside of the oven band with fixed speed drive and mounted on a trolley for removal to the side of the oven.
• Manual adjustment for brush pressure

2.3.16  Oven band

• Type Z47 wire mesh band
• Width 1200mm
• Oven band to be supported on skid bars in the baking chamber and on rollers on the return circuit

2.3.17  One – set of site wiring materials

> Biscuit Baking Ovens

2.4.  OIL SPRAY SYSTEM

FIG 6. tna oil spray with spinning discs

2.4.1 Oil spray machine, 1200mm wide

• Stainless steel construction
• Stainless wire mesh conveyor with auto tracking and tension
• Top and bottom spray units with spinning discs
• Mobile oil reservoir unit with heating
• High and low level sensors
• Filter system for surplus oil being returned to reservoir
• Mist extraction system

2.4.2 Drain conveyor

• 2.0m long, 1200m wide
• Stainless steel construction
• Stainless wire-mesh conveyor with auto tracking and tension
• Drain system to removable tank at the base of the conveyor

2.5.  COOLING CONVEYORS

FIG 7: Two tier cooling system

• Arrangement to provide 150% of baking time, 75m total length
• Inclined conveyor to deliver the crackers to a two tier cooling system
• Stacker feed conveyor
• Pneumatic web tensioning and tracking system
• 1300mm wide synthetic webs
• AC motor gearboxes with inverter speed control

2.6.  CRACKER STACKING MACHINE

• Chute with adjustable magnetic guides
• Adjustable star wheel stacking system
• Cracker guides for up to 20 lanes 

2.7.  PACKING TABLE

• 1400mm wide web
• Guides for up to 20 lanes
• Length 12.0m
• Automatic tension and tracking
• AC motor with inverter speed control

3. Selection of potential suppliers

The following are important considerations:

• Previous experience
• Supplier’s references
• Supplier’s location and sales/service network
• Budget and supplier’s price level

Usually 2-4 suppliers will be selected and asked to quote. The quotations can then be compared and a selection of the two best proposals will be made for detail discussions, visits to reference lines and the supplier’s factory.

4. Comparison of Quotations

The following is a typical comparison made between 3 suppliers, from Asia and Europe. The comparison highlights the differences in specification and commercial terms offered and will form the basis for negotiations with the selected suppliers.

5. Snack and biscuit line quotations

It is recommended that 2 – 3 suppliers are shortlisted for negotiations. Visits should be made to see the factories of the potential suppliers and to see relevant production lines in operation. At this stage the specifications of the equipment can be finalised with each supplier.

After the decision by the Buyer on the potential suppliers, the price and commercial terms of the contract may be negotiated, usually with two potential suppliers. A final decision on the supplier can now be made by the Buyer.

6. Commercial terms

The following are typical headings for a contract to buy a production line.

CONFIRMED ORDER

1. Scope of the order
2. Equipment specifications
3. Performance criteria
4. Programme Schedule
5. Price and payment terms
6. Delivery
7. Additional shipments
8. Exclusions
9. Guarantees
10. Liquidated damages
11. Liability
12. Confidentiality
13. Amendments in writing
14. Contract signatures: 

• Buyer
• Seller 

Our experience of over 40 years includes working with suppliers of biscuit, cookie and cracker production lines from Europe, USA and Asia. The following are some guide lines we have found valuable in selecting a supplier for a production line. An important part of our business now is sharing the experience of purchasing a production line and assisting bakeries in selecting suitable suppliers for new projects and negotiating successful contracts.

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Leading image: Packing table

Iain Davidson Baker Pacific November 2019