How a 2-in-1 spot and seam welder saves floor space, training time and setup headaches — and how the DuoFlex 20K does it.
20 kVA
rated capacity
1.8+1.8
mm max sheet
1–2000 A
weld current
Most sheet metal shops need two kinds of joints every day: quick spot welds on lap joints, and neat continuous seams where the finish matters. Many workshops buy a separate machine for each — and pay for it in floor space, training time and settings that drift from one operator to the next.
A 2-in-1 spot and seam welder puts both processes on one power source. Here is how the two processes differ, when each one makes sense, and how the CRUXWELD DuoFlex 20K combines them with a programmable controller.
Spot welding vs seam welding
The basics
Spot welding
Fast tack joints and repeated weld points
Lap joints on panels, cabinets, brackets
Gun goes straight to the joint — no re-clamping heavy parts
Seam welding
A continuous joint instead of isolated points
Cleaner visual finish along the edge
Straight or curved paths with uniform seams batch after batch
Why two separate machines cost you more
The problem
01
Floor space
Two machines, two footprints and two sets of cables in a busy shop.
02
Training time
Operators must learn two different machines and control panels.
03
Setup variation
Settings drift between machines and operators, so quality changes across shifts.
From the makers of this guide
Need a spot welding machine for your sheet-metal work?
The DuoFlex 20K system: two guns, one power source
Meet the DuoFlex 20K
The CRUXWELD DuoFlex 20K 2-in-1 spot and seam welder runs a handheld spot gun and a handheld roller seam option from one 20 kVA thyristor-based DC power source. A third gun is available as an upgrade.
Standard
Single-sided spot gun
Fast weld points on panels, cabinets, enclosures, kitchenware and light frames. Position the gun right on the joint.
Standard
Roller seam option
Continuous seams on straight or curved edges, with consistent seam formation across production runs.
Optional upgrade
Double-sided spot gun
Upper and lower copper electrodes clamp the joint from both sides for stronger, more consistent nuggets.
Digital microcomputer controller: set it once, repeat it every shift
Control
The digital controller with LCD display and program memory.
Most inconsistent resistance welds come from variation in timing and operator settings. The DuoFlex 20K controller lets you set the key parameters precisely and store multiple welding programs, so a repeat job starts with the same settings every time.
Weld time
How long current flows through the joint (1–999 ms)
Squeeze time
Clamping time before welding begins
Pre / post time
Stabilises the cycle, adjustable 0–999 ms
Weld current
Set to suit sheet thickness and joint design (1–2000 A)
Continuous or pulsed: two welding modes
Modes
Continuous mode
The standard choice for regular spot welding cycles and seam welding where stable output is needed.
Pulsed mode
Controls heat input on thinner sheets and sensitive joints, helping reduce marking and heat distortion.
Separate machines vs DuoFlex 20K
Side-by-side
Separate spot welder + seam welder
DuoFlex 20K (2-in-1)
Machines to buy and maintain
Two
One
Floor space
Two footprints
One compact unit
Operator training
Two machines to learn
One controller for both
Repeat jobs
Re-set each machine
Stored welding programs
Spot + seam on the same part
Move the part between machines
Switch the gun
Which gun configuration should you choose?
Buying guide
Standard 2-in-1
Single-sided spot gun + roller seam option
Mixed jobs: quick tack points plus neat continuous seams on panels, enclosures and ducts.
Add the double-sided gun
Upper + lower copper electrodes
The joint is reachable from both sides and you need stronger, more consistent spot nuggets in production or fixtures.
Not sure?
Share your job details
Send material, sheet thickness, joint design and production volume, and we will recommend the right combination.
Export-grade wooden crate for sea and air freight.
For export orders and long-distance shipments, the DuoFlex 20K can be dispatched in a strong, export-grade wooden crate that protects it from impact, vibration and handling shocks in transit.
Suitable for domestic and international shipments
Reduces the risk of transit damage
Recommended for sea and air freight
Get the DuoFlex 20K for your shop
Spot and seam welding from one 20 kVA machine, with stored programs for repeatable results. Ask about the optional double-sided gun and export packing.
GeM Registered OEM Manufacturer · 45+ years of welding expertise · Supported Worldwide
Frequently asked questions
FAQ
Is the DuoFlex 20K a spot welder or a seam welder?
Both. It combines a handheld spot welding gun and a handheld roller seam welding option in one setup, powered by one 20 kVA source.
What is the maximum sheet thickness?
The maximum welding capacity is 1.8 + 1.8 mm for lap joints, as per specification.
What power supply does it need?
AC 415 V ±15%, 50/60 Hz.
Can I save settings for repeat production?
Yes. The digital microcomputer controller stores multiple welding programs, so repeat jobs start with the same settings.
Does it support pulsed welding?
Yes. It offers continuous and pulsed modes. Pulsed mode helps control heat on thin sheet.
When do I need the optional double-sided spot gun?
When the joint can be reached from both sides and you want tong-type clamping with upper and lower electrodes for stronger, more consistent spot nuggets.
Need a spot welding machine for your sheet-metal work?
Pedal, pneumatic and hanging spot welders from 6 kVA to 35 kVA, engineered and tested in India with 45+ years of welding expertise. Call +91 88008 82983 or message us on WhatsApp.
CRAZY IN LOVE WITH WELDING. Ramakant has a diversified background with industrial experience in welding and production management. He holds a master's degree (M.Tech.) in metallurgy and welding technology from SLIET University. He has experience in a number of industries, including power generation, defense, construction, mining equipment, and heavy engineering fabrication. He holds the positions of welding engineer, quality and inspection officer as well as general management. He has written technical welding articles, contributed to the various welding committees. For the past eight years, Ramakant has been a technical consultant, trainer, and spokesperson for Cruxweld.
