In-Depth Analysis of Stainless Steel Water Bottle Stretching Process --- The Height Factor

Every cup holds a story, and life has its warmth. Hello everyone, and welcome to "Dong Dong's Cup Talk" As I've shared more and more content with you all, writing these pieces has become increasingly challenging. So today, I've invited a true expert, Engineer Zhang. He is the technical authority in our factory and holds a deep affection for our work. https://www.zhanyict.com/en/ProductsDetail-VB-10524.htmlHe's here today to share insights about the stretching process for stainless steel water bottles. Let's give a warm welcome to Engineer Zhang!

Hello everyone! I'm Old Zhang, and I've been in the stainless steel water bottle industry for a full twenty years. For these two decades, I've focused on practically nothing else but grappling with the craft of "stretching." From the earliest manual punch presses to today's intelligent multi-station continuous stretching machines, from watching seasoned masters rely on experience and "listening to the sounds" to the current era of digital, parametric precision control – I've witnessed with my own eyes and worked hands-on with every evolutionary step of this process. https://www.zhanyict.com/en/ProductsDetail-VB-10524.htmlToday, I want to talk systematically with you all about the ins and outs of the stainless steel water bottle stretching process. I hope to offer some inspiration to those new to the field and also exchange ideas and learn from the veteran masters. [Cue applause here!]

II. The Height Variable: It's Not Just About Pulling Further

Taking a cup body with the same 70mm diameter, stretching it to 80mm versus stretching it to 300mm are entirely different concepts. https://www.zhanyict.com/en/ProductsDetail-VB-10524.htmlThis tests the stability of material flow and the tensile strength.

Finished Height (mm): 80mm - 100mm

Equipment & Process Selection: A single-action sheet metal punching machine is sufficient.

Technical Challenges & Analysis: Short cup body, small degree of deformation, smooth material flow. https://www.zhanyict.com/en/ProductsDetail-VB-10524.htmlThe process is relatively simple, yielding a high rate of non-defective products.

Finished Height (mm): 150mm - 200mm

Equipment & Process Selection: A stretching machine equipped with a hydraulic blank holder device.

Technical Challenges & Analysis: This enters the realm of deep drawing. Precise control of blank holder force is required to balance the conflict between wrinkling and tearing/rupture. https://www.zhanyict.com/en/ProductsDetail-VB-10524.html2-3 stretching steps may be necessary.

Finished Height (mm): 280mm - 300mm

Equipment & Process Selection: High-tonnage deep draw hydraulic presses (500 tons or above) or multi-station continuous stretching machines.

Technical Challenges & Analysis: This is the ultimate test of both technique and equipment.

1. Material: Must use stainless steel with excellent deep drawability, https://www.zhanyict.com/en/ProductsDetail-VB-10524.htmlspecifically DDQ (Deep Drawing Quality) grade or even DDS (Extra Deep Drawing) grade.

2. Molds: The coordination precision between multiple mold sets must reach a micrometer level.

3. Lubrication: Requires stretching oil with extremely strong adhesion and top-tier extreme pressure (EP) performance to provide protection throughout the process.

4. Annealing: https://www.zhanyict.com/en/ProductsDetail-VB-10524.htmlIntermediate annealing is absolutely essential. Otherwise, the material becomes hard like tinplate and will crack upon the next stretch.