To isolate a channel and complete a circuit in a manifold, plugging an open cross-hole is an option. Mostly applicable in a drilled manifold or a bonded manifold where a layer can be eliminated, there are many ways to make a permanent seal.

Engineers and designers make cross-drilled manifolds to distribute fluid or gas evenly across several channels. This enhances the manifold's overall functionality. However, some circumstances might merit plugging some cross-drilled holes. Those involve different end-uses, control, and even performance overall.

CUSTOMIZABLE FOR SPECIFIC & SPECIALIZED APPLICATIONS

Designers need to keep in mind versatility when it comes to their manifolds. Sometimes, users can have more than one purpose for that manifold where they need to tailor those settings. By strategically placing plugs into certain areas, users can meet the specific demands for needed applications.

MORE CONTROL

To allow for better regulation and optimization, plugging these channels serves to grant users more precise control over the manifold's fluid/gas flow.

IMPROVE OVERALL PERFORMANCE

When plugging unnecessary channels and holes, this can minimize pressure drops and streamline a flow path. This often results in better manifold performance.

1  Assess by examining and identifying which channels need plugging. Consider any specific requirements the applications needs as well as performance goals.

2  Select the right high-quality and best suited plugs for the operation.

3  Clean the cross-drilled holes and the surrounding area to remove any contaminants that could cause detriment to the sealing process.

4  Apply the appropriate sealant to the plug's threads before inserting.

5  Securely tighten the plug using the recommended torque specific to that plug to prevent either over- or under-tightening. These can indelibly affect the quality of the seal.

6  Conduct thorough testing to ensure that the manifold has the correct flow path and can achieve your performance objectives.

Several types of plugs exist that users can utilize towards their specific goals. Below, we detail some of the most popular types our customers use most often.

PRESS-IN BALL

Most use press-in ball (PIB) plugs when versatility and flexibility matter in a manifold's operation. They consist of a spherical or ball-shaped head attached to a cylindrical stem. This grants users easy insertion into the channels and provide an effective seal while providing a removeable option. In some cases, users need to temporarily disengage channels and customize fluid/gas pathways for particular operations. PIB plugs can give users this ability.

Most often, these plugs come in stainless steel or ceramic, making them a more cost-efficient option for those seeking a level of flexibility.

We recommend that when it comes to interference fit, the plug should be tested for each application. However, a .003” interference fit for .0625 ball is appropriate for ULTEM and polycarbonate. Tough plastics like acetal and polypropylene can tolerate more.

We do not recommend this as a good option for acrylic manifold applications because of potential cracking during installation and removal.

PLASTIC PLUGS

Plastic plugs serve as the most common approach for ensuring plugged channels. Typically made of parent material, these plugs are pressed into the manifold then are either bonded using solvent bonding or adding UV cured adhesive on the top of the plug. Although this does not grant the user the flexibility for later removal, it does work to ensure a tighter seal for prolonged use.

We recommend avoiding amorphous plastics if using these types of plugs. Manifolds may stress crack because of high force exerted on plastic. However, many have marked this as a nice solution for semi-crystalline plastics.