Design Guide for Plastic Manifolds

The following guide is intended to provide a general approach to the design of plastic manifolds.

Design Guide for Plastic Manifolds

Users should undertake appropriate verification of their specific design to ensure suitability for the application. This guide is not intended to confirm fitness for a particular use. All the data contained herein should be used as a reference only.

Getting Started with Manifold Design

What are Plastic Manifolds?

Plastic manifolds are used for precision control of liquids and gasses. They have many applications from medical and life sciences to aerospace and industrial. Manifolds are

the response to the need for more compact, easier to maintain devices. They allow a design engineer to take what are originally discrete components connected together with tubing and consolidate them into a single integrated assembly of plastic.

Controlled Fluidics produces plastic manifolds as a single layer or multilayer assembly. Single layer manifolds utilize common machining operations like drilling and milling to produce an internal straight network of channels. Multilayer manifolds allow for internal geometries, i.e. curved channels, not possible only through machining. Created layer by layer, the multilayer manifolds are bonded together with heat, pressure and time.

Single Layer Manifolds

Multi Layer (Bonded) Manifolds

Why use a Manifold?

Medical device manufacturing starts with an idea for a process solution to a diagnostic challenge. Experimentation begins on a breadboard; connecting pumps, valves, sensors with tubing to complete a testing circuit.

With success, the process coalesces into a working medical device. Historically the internal fluidic circuits retained much of the same approach as the bread board. Discrete components connected together with tubing. Revision 1 often retains this approach. It helps support development with ease of changes, multiple variants, and upgradable components.

While the tubing approach is a working solution, it suffers from important limitations. Assembly time is high. As more tubing is added the difficulty of visualizing the fluidic system increases. Ultimately the tubing runs dominate the entire visual field inside the device. Field servicing is more time consuming and difficult. Overall device size grows. Each tubing run requires 2 connection points. Each connection point is a potential source of leaking

Today’s medical device design utilizes either a drilled manifold or bonded manifold for tubing reduction or outright elimination. Components are mounted directly on a single monolith of plastic, with all connections internal to the manifold. Size is optimized while allowing for visualization of the fluid circuit. Leak points are minimized to the components mounted on the plastic manifold and inputs and outputs. Field servicing is simplified to exchange of components.

Manifold Design

Requesting a Quotation

You can request a quotation through our quote form, by emailing, or by calling us at (603) 673-4323. Please be considerate on your request, quotes require time and effort by our engineers.

Quote options:

  • Full Design Request: Customer supplies basic schematic and components. Controlled Fluidics provides the complete layout. A full design request will include a quote for the design and an estimate for manufacturing the manifold.
  • Design Complete: Manifold design is provided by the customer. Controlled Fluidics can provide design for manufacturing support as an add-on. Includes a quotation for the manifold.

Full Design Request

Have a sketch of the fluid path but don't know where to begin? We can help by designing the entire manifold including valves and porting from your schematic. The initial quote will be for the design effort and a rough estimate for the manifold cost.

Steps of Full Design Request

  1. Request design.
  2. We quote the cost of the design
  3. We design the manifold.
  4. We present the manifold to you, with one round of iterations for customer changes.
  5. Design is modified as needed.
  6. Final design is presented to the customer
  7. We finalize the production cost of the manifolds.

What we will need from you

  • A schematic diagram of the flow paths.
  • List of components.
  • Physical space constraints on the manifold.
  • Operating parameters.
    • Pressures
    • Temperatures
    • Chemicals
    • Flow rate
    • Valve sizes
    • Liquid or gas (Media)
  • Sensing requirements.
  • Special tolerance requirements. (±.005”/125 microns standard)
  • Quantity requirements
  • A description of the functions/purpose of the complete fluidic system isn’t always required but can be very helpful. The more our engineers understand your system the more they can help assure the manifold fully meets your design purpose

Design is Complete

Fully completed design ready for manufacturing.

What we will need from you

  • How many pieces are needed? (We will appreciate exact quantities)
  • Is this a one-time order or an annual order?
  • Lead time requirements.
  • Material Selection.
  • 3D solid model of the part. (Preferably step format)
  • 2D model (pdf) with additional information not shown on the 3D model.

2D and 3D Models 

2D models are often necessary to add detail to the design but a 3D model is required to make a manifold. When a 2D and 3D model conflict, the 3D model is used to make the final decision.

Details to put in a 2D Model:

  • Tolerancing
    • Our standard tolerance is +/- .005 (130 micron) when not specified.
    • We can support tighter tolerances but they must be specified in a 2D model accompanying the 3D model. Tighter tolerances may cost more, apply them only where necessary.
  • Surface finish
    • Our standard finish is 32 microinch RA (.8 micron). For more on finishes check out Surface Finish (our typical finishes), Finishes (alternative finish techniques) or Clarity (levels of clarity).
  • Material
    • Please specify your material choice on the 2D drawing
  • Location of threads
    • Please specify all threaded holes.
  • Thread sizing
    • Threads are assumed to be class 2B threads.

Design for Manufacturer Add-on

We offer a DFM option for those who have a basic layout but need further refinement. This is a limited design review focused on lowering cost and ease of manufacturing. No functionality checks.

Can we put in a pump instead of a actuator?


All About Materials for Manifolds

  • Drilled manifold material choices
  • Bonded manifold material choices
  • Material sizes
  • Material colors
  • Material cost
  • Material certifications
  • Availability
  • Chemical resistance
  • Radiation resistance
  • Temperature resistance
  • Stress sensitive plastics
  • Misc information
  • Ease of machining


  • Intro - Bonded vs machined vs printing
    • Critical feature density
    • Printing
      • Good for coring out parts (metal printing)
      • Poor finish, Manifolds need good finish. 
    • Compare and contrast approaches
      • Footprint
      • Flexibility
      • Finishes
      • Tubing approach
      • Chemical resistance
      • Temperature resistance
      • Accuracy
      • Threads
    • How to handle a manifold
    • Delivery
      • Batch Flow
  • All about machining
    • Size of part
    • What happens when parts crack
      • Polariscope
      • Causes
    • Drilling
      • Length limitations
      • Dia. limitations
  • All about bonding
    • Number of layers
    • Max/Min size for bonding
      • Diminishing returns.
    • Pressure limitations
      • Common working pressures
    • Feature size
    • Bonded in components
    • Fixturing requirements
    • Datum location
    • Injection molded blanks
    • Channel 
      • Intersections
      • Size and sizing
      • Finish
      • Shapes
        • Liquid app
        • Pneumatic app
      • alignment
    • Bubble traps/reservoirs/accumulators
      • Size
      • supports
      • cleanout
    • Feature spacing
      • channel to channel
      • channel to reservoir
      • channel to edge
    • Features on bond line
      • Threads
      • Ports
      • channels
    • Cost drivers
      • Material
      • Number of layers
      • Feature density
    • How to bond
      • Thermal
      • Solvent
      • Tape/PSA
      • Laser
      • Vibration
      • Adhesive
    • Defects
      • Delamination
      • Bubbles
      • Foreign objects
    • How to inspect a bond line
      • Expected strength
      • Torque test
      • Visual check
      • Pressure check
      • Decay Test

Design Approach

  • How to request a quotation
    • Design complete
      • DFM
      • Quantity
      • Material choice
      • Solid model and pdf
    • Full design request
      • Working pressure
      • Flow rate
      • Foot print
      • Liquid or gas
      • Chemical exposure
      • Sensing requirements
      • Schematic
  • Tolerancing
  • Surface roughness
    • Bottom of port
    • Valve seat sealing face
  • Good practice
    • Dimension to bottom of counter bores
    • Avoid large flanges
    • Control of insert insertion depths
    • Avoiding chemical exposure like thread locker
    • Sharp channel blends
  • Clarity
    • How to make parts clear - polishing
    • Definition of clear
    • Other finishes – blead blast, tumble, as machined. 
  • Connections
    • Straight Tubing
    • Push to connect, john guest
    • Value plastic fitting
    • Beswick/memco fitting
    • Barb fitting
    • Full machined barbed fittings
    • port design
      • upchurch, high/low pressure
        • torques
        • thread engagement
      • NPT
      • Ministac
  • Marking
    • engraving
    • printing
    • laser marking
    • coloring & logos
  • Plugging
    • Press in Ball, ceramic or SS
    • Plastic plug
      • Solvent
      • UV cured 
      • press
  • Cleanliness of manifolds requirements
    • Methods of cleaning
    • Sterilization
      • Oxygen service
  • Avoiding stress cracking
    • Material choice
    • Proper coolant
    • Only plastics machine shop
    • Proper machining
    • Threading care, tapered
    • Chemical resistance
  • threading
    • drilled/tapped
    • self tapping screws Stanley Threaded Fasteners for Plastics,
    • inserts – always last
      • straight
      • npt
      • heat affected zone
      • Heli coils – tang-less
      • Examples of ways to install an insert to support a valve mount.
        • Clippard
        • Small valves - smc
  • torques


  • Testing
  • Cost
  • Components
    • Valves
      • Design considerations
        • Pressure/vac range
        • Flow requirements Cv, sizing
        • Internal volume
        • Dead volume
        • Operating temperature
        • 2 way or 3 way
        • Mount
        • Cost
        • Operating media
          • Gas
          • Liquid
            • Chemical resistance
            • Particulate
            • Viscosity
            • temperature
      • Electrical requirements
        • Voltage
        • Power consumption
        • Duty cycle
        • Connections
        • Response time
      • Type
        • Poppet Valve
        • Diaphragm Valve 
        • Rocker diaphragm valve
        • Pinch valve
        • Lever valve
    • Pumps
      • Types
        • Syringe pump
        • Diaphragm Solenoid pumps
        • Diaphragm Motor
        • Gear
        • Rotary vane
        • Peristalitic
        • Rotary ceramic piston
      • Design considerations
        • Accuracy
        • Precision
        • Repeatability
        • Cost
        • Wetted materials, chemical resistance
        • Pressure requirements
        • Speed/increment – dispense/aspirate
        • Electrical requirements
        • Foot print
        • Mount
        • Life cycle
        • Self priming
        • Operating temperature
        • Fluid
          • Liquid
          • Gas
          • Viscosity
          • temperature
    • Wetted materials
    • Pressure sensors
    • Flow sensors
    • Check valves
    • Pressure relief
    • Fittings
      • Barbed
      • Flanged fitting – omin lok
      • Super flangeless fittings – upchurch
      • Heat form Teflon flare - diba
    • Bubble sensors
    • Orifice – Lee/Bird
    • Calculating flow in valves, tubing, Reynolds number


  • Material specification sheets
  • Property comparison
  • Fittings
  • Inserts