Sigma Flex Handheld Induction Cap Sealer
A portable, manual induction cap sealer for labs, batch runs, and startup production. One universal sealing head covers caps from 20 mm to 100 mm.
Sigma Flex from Sigma CapSeal produces tamper-evident, leak-proof seals across a wide cap range. No chiller, no water, and no complex setup. Plug it into a standard 230 V outlet, set the timer, and seal. Sigma CapSeal builds it, with more than 50 years of induction sealing experience and clients in over 85 countries.
20-100 mm
Cap Range
4-8
Bottles/Min
8 kg
Portable
24/7
Duty Rated
20-100 mm
Cap Diameter Range
4-8
Bottles Per Minute
8 kg
Net Weight
230 V
Single Phase
Air-Cooled
No Water Needed
24/7
Continuous Duty
A Production-Grade Sealer You Can Carry
Sigma Flex is a manual induction cap sealer. You hold the sealing head and seal one container at a time. It suits laboratory work, small batch runs, startup lines, and offline seal testing.
It weighs 8 kg, fits on a tabletop, and ships with a carrying case. A single universal head seals every cap from 20 mm to 100 mm, so one machine covers your full bottle range across many container types.
How the Sigma Flex Works
Induction sealing bonds a foil liner to the container mouth using heat from an electromagnetic field, not a flame. The coil heats the foil inside the cap, the film melts, and it fuses to the rim. The result is an airtight, tamper-evident seal in one motion.
1
Place the Sealing Head
Set the handheld sealing head on the container cap. No fixtures and no alignment tools.
2
Press and Seal
Press the switch on the handle. The countdown timer starts and the induction field heats the foil liner.
3
Verify Seal Quality
Check the first few caps. Peel a liner and read the bond for an even, complete seal.
4
Lock In the Setting
Set the timer and cap torque once the seal is clean. Repeat the same setting for the full run.
A clean seal depends on dwell time and cap torque. Add time for a weak seal. Cut time if the foil scorches. Once set, each run stays consistent and auditable for quality records.
See Sigma Flex in Action
Watch the quick demo of the sealing process, then download the brochure for full specifications.
Sigma Flex Brochure
Full specifications, features, and application notes in a single PDF for your evaluation file.
Key Features and Engineering Advantages
The capabilities that make Sigma Flex a production tool for labs, batch runs, and startup lines.
Portable and Line-Relocatable
8 kg, 13 inches wide, with a carrying case. Seal at a bench or a line, and move between rooms or sites in minutes.
Waterless, 100% Air-Cooled Coil
No chiller and no water. This removes a common downtime source and cuts the maintenance load on your team.
Universal Sealing Head, 20–100 mm
One universal head seals the full range with no head swaps. It standardizes sealing across many SKUs.
Low-Loss Coax Cable
More power reaches the coil and less turns to waste heat. The cable runs longer for taller containers, and the heat cycle runs shorter, so throughput climbs.
Digital Soft-Touch Panel
A simple interface any operator learns in minutes. The digital up and down timer records the exact seal time for audits.
24/7 Plug-and-Play
Continuous duty rating. Runs on single-phase 230 V AC with no tuning tools. Set the timer and seal.
Cap and Container Compatibility
Will it seal yours? If the cap holds a foil induction liner, the answer is yes. Sigma Flex handles a broad set of closures, container materials, and liner types.
Caps & Closures
- Child-resistant caps (CRC)
- Dome caps
- Sports caps and spout caps
- Snap-on caps
- Flip-top caps
- Standard continuous-thread screw caps
Container Materials
- HDPE and LDPE bottles
- PET containers
- PP containers
- Glass containers
- Plastic caps with a foil liner
- Seal depends on the foil liner, not the shell
Liners & Sealing Heads
- Two-piece foil induction liners
- One-piece foil induction liners
- Heat-seal wads matched to cap size
- Flat sealing head
- Tunnel sealing head
- Custom head for unusual closures
Sigma Flex in Use
Replace the placeholders below with actual machine, sealing head, and seal-detail photos before publishing.
Control Unit & Sealing Head
Handheld Sealing Head
Digital Soft-Touch Panel
See Sigma Flex Seal Your Caps
Bring your cap geometry and liner material, and our applications team will show Sigma Flex sealing your closures. Confirm the right liner, dwell time, and head style for your container before you buy.
- Machine matched to your cap diameter and closure type
- Liner compatibility check for your material
- Timer and cap torque guidance for a clean seal
- Applications engineering Q&A
Talk to Sigma CapSeal
Engineering-led support with decades of field experience and responsive after-sales service.
Where Sigma Flex Is Used
Each industry values a different outcome. Sigma Flex seals across regulated and everyday packaging in small runs and lab settings.
Healthcare & Pharma
Tamper evidence and a moisture barrier for tablet and syrup bottles in R&D labs and offline QC.
Nutraceutical
Reliable foil seals on supplement and powder bottles for pilot batches and small runs.
Food & Beverages
Freshness and leak prevention for sauce bottles, syrups, and powder jars.
Dairy
Clean, airtight seals on dairy cups and bottles that block spills in transit.
Personal Care & Cosmetics
Leak protection and theft evidence for lotions, creams, and oils.
Agro Chemicals
Secure seals on agrochemical bottles across mixed cap sizes.
Petro Chemicals
Foil seals for petrochemical containers in small batch packing.
Speciality Chemicals
A reliable barrier under the cap for specialty chemical bottles and jars.
A Clear Upgrade Path Across the Sigma Range
Sigma Flex is the entry point in the Sigma sealing range. As your volume grows, you move up without changing supplier. Sigma Pro, Sigma Eco, Sigma Neo, and Sigma Jet add automatic and inline sealing for high-speed lines.
You start manual today and scale to automatic later. For GMP and CFR 21 Part 11 production, the Sigma Jet CFR21 model adds compliant, auditable sealing on the same platform you already know.
Sigma Flex Technical Specifications
Parameter summary for engineering evaluation and line specification.
- Parameter
- Sigma Flex Specification
Machine Type
Handheld manual induction cap sealer
Cap Diameter Range
20 mm – 100 mm (universal sealing head)
Sealing Capacity
4 to 8 bottles per minuter
Cooling
100% air-cooled, waterless
Control Panel
Digital soft-touch membrane with digital up/down timer
Cable
High-efficiency, low-loss coaxial cable
Net Weight
8 kg / 18 lb
Power Input
230 V AC ± 10%, single phase, 50/60 Hz
Dimensions
13″ W x 20″ D x 6″ H
Duty Rating
Continuous, 24/7
Head Options
Flat, tunnel, custom
In the Box
Sealing head, control unit, carrying case
Configuration varies with cap and closure type. For liner selection, custom head tooling, and application support, contact Sigma CapSeal applications engineering.
50+
Years of Experience
85+
Countries Served
Global
Spare Parts & Service
1974
Engineering Since
Less Maintenance, More Output
Fewer maintenance tasks and faster seal cycles lower your running cost over the life of the machine. Total cost of ownership beats a low sticker price.
Why Choose Sigma Flex
Cheap handheld sealers target hobby and very low volume use. They lack a duty rating and a service path. Sigma Flex carries a 24/7 rating and a 50-year build standard. You buy a production tool, not a gadget.
Sigma CapSeal built its first heating equipment in 1974 and now serves clients in over 85 countries. That reach means spare parts and after-sales support reach your plant fast. A handheld sealer is only as good as the support behind it.
Frequently Asked Questions: Sigma Flex
Common questions from packaging engineers, QA managers, and packing teams evaluating Sigma Flex.
Can Sigma Flex seal non-metallic or plastic caps?
Yes, as long as the cap holds a foil induction liner. The induction field heats the foil inside the cap, not the plastic shell. Sigma Flex seals plastic caps that contain a foil liner. It does not seal caps with no foil liner.
What cap sizes can Sigma Flex handle with the universal head?
One universal head seals every cap from 20 mm to 100 mm. You do not swap heads between bottle sizes. For unusual cap shapes, flat, tunnel, and custom heads are available.
What foil liners does Sigma Flex require?
Sigma Flex bonds standard two-piece and one-piece foil induction liners, also called heat-seal wads. You match the liner to the cap diameter and the container material. The correct liner plus the right dwell time set your seal strength.
Air-cooled versus water-cooled, which is better?
Air-cooled is better for handheld, lab, and low-to-medium volume work. It needs no chiller, no water lines, and less maintenance. Sigma Flex uses a 100% air-cooled coil. Water-cooled sealers suit only very high-speed continuous lines that run all day at peak output.
Is a handheld sealer suitable for continuous production?
Sigma Flex carries a 24/7 duty rating and seals 4 to 8 bottles per minute. This fits batch runs, labs, and startup lines. For high-volume continuous output, the automatic and inline models in the Sigma range, such as Sigma Jet, are the better fit.
How portable is Sigma Flex?
It weighs 8 kg, measures 13 inches wide, and ships with a carrying case. You can seal at a lab bench in the morning and a packing line in the afternoon, and move it between rooms or sites in minutes.
Match Sigma Flex to Your Caps and Containers
Talk to a Sigma CapSeal applications engineer. Bring your cap geometry, liner specification, and closure type, and we will confirm fit and the right head for your line.