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Comparison Guide: Sterile Tube Welders vs. Aseptic Connectors

A survey of bioprocessing industry professionals asked which method they prefer for their connection needs: sealable and weldable tubing or aseptic connectors. Respondent opinion was almost equally divided with 52 percent choosing aseptic connectors and 48 percent preferring sterile tube welding.1 So how do you determine the right method to maintain batch integrity and maximize manufacturing flexibility while avoiding product loss, system downtime, and potential for operator error? Below are key factors to consider in selecting the best approach for your application.

Factor Sterile Tube Welding Aseptic Quick Connectors
Set-up/Use Time

Move sterile tube fuser into position, obtain and install the correctly sized tubing holder, initialize the welder, load tubing, weld, cure time (~4-7 minutes total)

Set up/use time multiplied by hundreds of welds a week affects overall productivity (e.g., 100 welds/week x 4 minutes = 6.67 hours operator time for welding)

Aseptic connectors are sterilized and ready to go in tubing/bag assembly, requiring only seconds to connect and actuate

System Flexibility

Connection can be made at any time or any place in the tubing

Welder must be set up for correct tubing size and material

Tube holders are gauged to specific sizes (e.g., 3/8” x 5/8”)

Only the same-size tubing (same ID and OD) can be welded together

Single-use connectors are available that allow for flexibility between different types and sizes of tubing

No reducers required

Acquisition/Use Costs

Capital equipment and ancillary equipment costs range from a few thousand dollars to tens of thousands per welder in each clean room

Single-use blades cost

Staff time for set-up and use or downtime if system jams or locks

Back-up welder if needed

Maintenance cost

Higher variable costs than blades

No capital expense

Factor Sterile Tube Welding Aseptic Quick Connectors
Maintenance Requirements

Welders must be in good working order

Welder manufacturer’s warranties for regular preventative maintenance of equipment

Need backup welder during maintenance or out-of-service episodes

Single-use disposable connectors ready to use

No maintenance required

Extractables Package

Very limited package

Published studies on the impact of thermal welding process to the flow path of the tubing

Most manufacturers provide a published extractables package to understand potential effects on cell lines.

Contamination Risks

Nonconformance to manufacturer’s recommendations might raise contamination risk due to:

- Placing tubing with the incorrect diameter in the tube holder. This can cause small pinholes in the weld, due to pinching or squeezing the tubing out of the holder during the weld process

- Welding different tubing types together, which can lead to weld failure

Little to no contamination risk because validated aseptic connectors maintain a sterile boundary between two adjoining single-use systems

Staff Training

Welders require operator training to ensure proper technique, minimize errors and to safely use the equipment

Largely connect-and-go, self-contained components with minimal operator training required

Potential for Operator Error

Not following manufacturer’s recommendations can lead to the following potential operator errors:

- Using wrong tube holders for size of tubing

- Using incorrect tubing: silicone, mismatched TPE

- Using incorrect tubing type setting on the welder

- Not using long enough tubing

- Putting tension on the tubing

- Inserting the blade incorrectly or reusing single-use blades

Not following manufacturer’s recommendations can lead to the following potential operator errors:

- Using process fluids outside of the connector’s chemical compatibility specifications

- Not fully attaching connector to tubing

- Applying too much side load

Materials Considerations

Minimum tubing lengths might be required to fit tubing into welder

Must connect same materials (e.g., C-Flex to C-Flex)

Costly C-Flex tubing is often used for welding

Silicone can’t be welded because the material burns

Must know each vendor’s type/size of tubing to ensure compatibility of supplies

Any tubing length—no minimums required

Connect to any type of tubing, including silicone, and different types of tubing (e.g., silicone to C-Flex)

Connect different hose barb sizes (e.g., one side with ¾” hose barb and the other with a ½” hose barb)

Genderless connectors eliminate the need to carry male/female components

Connectors from the same family can be interconnected

Level of Validation

New sterile tube welders require onsite validation but come with a full weld validation package

No new product contact material will be introduced into the process

Aseptic connectors are ready to use and have been validated for material biocompatibility, extractables, sterility, and leakage

New product contact material might need to be introduced and tested if the connector material has not been used elsewhere in the process

Wet Welding

Weld on a new bag at any time or any place in the tubing line (e.g., during a perfusion process). Sufficient tubing length is required to make the weld

A pre-assembled, sterilized manifold of aseptic connectors facilitates adding additional lines to a process

Operating Conditions

Ensure sufficient room and ample tubing to place welder near the process due to the size of the welder

No extra space, materials or equipment required for connector use

Product Weight

~25 - 35 lbs. for welder

Negligible weight per connector

When properly applied, either sterile tubing welders or aseptic connectors can create reliable connections. Therefore, factors such as ease of use, potential for downtime, risk for operator error, cost and supply management take on added importance for system designers and processors. Aseptic connectors—particularly genderless models—deliver the flexibility, ease of use, reliability and cost efficiencies sought by today’s bioprocessors.

About CPC

CPC is a leader in single-use connection technology, offering a wide variety of bioprocessing connection solutions. Innovative designs easily combine multiple components and systems including process containers, tubing manifolds, transfer lines, bioreactors and other bioprocess equipment. Sterile fluid connections from CPC range from 1/8” to 1” flow configurations.

For more information, visit:

Contact CPC at:

Or contact one of our bioprocessing specialists at:

CPC Corporate Headquarters CPC Europe CPC Asia Pacific References:

1. “Friday’s Five Questions for the Biotechnology Community” Survey. Aspen Alert. Issue 2441: 8 June 2017.

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