High-speed web inkjet printing requires stable production, predictable uptime and efficient roll handling. On the Contiweb CD-N Non-Stop Unwinder, splice preparation is extremely fast, safe and consistent. The entire process takes just two minutes and can be completed while production continues — with a proven splice success rate of 99.8%.
This page explains how splice preparation works on the CD-N and demonstrates the difference between overlap and single butt splice preparation. It also shows why manual roll changes on mono unwinders cause significant downtime, and how the CD-N eliminates these issues entirely through precise, automated non-stop unwinder splicing.
1. Why manual roll changes on mono unwinders cause downtime and introduce risks
On mono unwinders, every roll change requires the operator to prepare the splice manually. This process is time-consuming, creates paper waste and introduces several operational risks:
- Inconsistent splice quality (fully dependent on operator skill)
- Higher chance of splice failure
- Risk of web breaks at high inkjet speeds
- Long webbing-up times if the web snaps
- Stop-based workflow: production MUST be halted for every roll change
Even in well-run environments, a manual roll change quickly consumes 15 minutes or more – from slowing down the press before the roll change to ramping up to full production speed after the splice - of valuable production time.
Below is a visual overview of the steps required for a typical manual roll change on a mono unwinder:
2. How the Contiweb CD-N prevents downtime and bad splices
The Contiweb CD-N is designed to remove all unnecessary stops and risks associated with manual splicing:
- Automated, machine-controlled splice → 99.8% splice success
- Only 2 minutes of splice preparation
- Preparation can be done while printing, increasing operator flexibility
- Uniform, machine-guided splice preparation, ensuring consistent, repeatable results
- No heavy lifting, no cranes required
- Operator-friendly working height and ergonomic design
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No production stop required for roll preparation
3. Splice types and preparation explained
Before diving into the individual workflows, it is important to note that Contiweb supports two splice types commonly used in high-speed digital book production: the overlap splice and the single-sided butt splice. Both are proven splice methods designed to ensure stable running at high web speeds, but each is preferred by different press manufacturers and finishing lines. Depending on the press platform and the sensitivity of downstream equipment, Contiweb supplies the splice technology that best matches the required performance, stability and web handling characteristics.
3.1. What is an overlap splice?
As shown in the illustration below, an overlap splice joins the new web to the running web using adhesive tape, with only a minimal tail from the expiring web placed over the new web. This controlled overlap ensures robust splice integrity, excellent performance at high inkjet speeds, and reliable, predictable behaviour across a wide range of paper grades.
3.2 Simplified workflow overlap splice preparation on the Contiweb CD-N:
Preparing an overlap splice on the CD-N is quick, straightforward and highly consistent. The design of the splicer naturally leads operators through the same sequence every time, ensuring uniform splice quality. The simplified steps are shown in detail in the video further down this page.
- Open the splicer head.
- Pull the new web over the vacuum bar of the splicer head.
- Trim the leading edge straight by cutting along the groove of the vacuum bar.
- Apply tape across the full web width and remove the backing film.
- Close the splicing head.
3.3 Video overlap splice preparation on the Contiweb CD-N Non-Stop Unwinder
3.4 What is a single-sided butt splice?
A butt splice joins two substrate edges exactly edge-to-edge using tape, without any overlap. As shown in the illustration below, a single-sided butt splice joins the new web and the running web edge-to-edge, with no tail. The adhesive tape bridges both paper ends and creates a clean, flat transition. This allows the web to pass smoothly through the press and downstream equipment, reducing the risk of disturbance and enabling stable running at high production speeds.
3.5 Simplified workflow single sided butt splice preparation on the CD-N
Creating a single-sided butt splice on the CD-N is fast, easy and consistently precise. The splicer’s ergonomic setup helps operators follow a repeatable routine, resulting in a stable, high-quality splice. A detailed walk-through is available in the video below.
- Open the splicer head.
- Pull the new web over the vacuum bar and position the butt splice tool.
- Trim the edge of the new web straight by cutting along the groove of the vacuum bar.
- Cut the adhesive tape and place it on the vacuum bar.
- Pull the web onto the tape and close the splicer head.
3.6 Video butt splice preparation on the Contiweb CD-N Non-Stop Unwinder
4. Learn more about Contiweb's auto-splicing solutions for web inkjet
Discover how the CD-N helps book printers and commercial printers maximise uptime and stabilise production.
