Technique

INTRODUCTION

The Hofmann Handtufting (Hand Tufting) gun has been around since the 1980’s. It uses a combination of a feeding system with pneumatic (air) and cutting actions to produce a cut pile tufted rug, carpet or wall hanging. The hand tufting gun has been progressively developed and improved since its original design to todays machine that is very reliable, easy to use and versatile. The ability to switch from cut pile to loop pile or change the height of pile very quickly makes this the most popular technique and world leader that it has become. The ability to switch from an even sided cut pile to a “J” tuft is another attraction and feature of the Hofmann Handtufting Gun.

1. Any colour can be worked
2. Any yarn strength up to nm 0.3 (yarn diameter 6mm)
3. Any pile height from 9 mm to 74 mm “J” tuft.
4. Any carpet size, to 20m x 30m seamless
5. Any carpet form, round, with corners, irregular shapes.
6. Any pattern, beginning with the finest embroidery motifs to large area patterns
7. Any high low structure in cut and loop pile
8. Any material (wool, silk, synthetic)
9. Any pile weight up to 10 kg per square metre
10. A practiced person can produce up to 10 square metres per day

The list could go on, but one can see that there are almost no limits for producing the most diverse types of carpet, rugs and wall hangings for floor, wall and ceiling.

USES

— manufacture of individual carpets

— Rapid and economical patterning of carpet designs

— testing carpet yarns in spinning mills

– tufting patterns into bath mats

— Production of sample collections

— processing various remnants into carpet

— As training aid in textile classes and art and design departments of schools, colleges and universities.

Hand tufted carpets are consisting of two basic elements

1. The woven carpet carrier (backing)
2. The pile yarn punched through the base

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THE VELOUR HAND TUFTING GUN

This machine from the factory HOFMANN HANDTUFT-TECHNIK KG is a so called single needle hand tufting machine or handtuft gun operating on the air jet principle. The pile yarn is fed through a hollow needle. This needle penetrates the stretched base with a precisely designed supply feed wheel the required amount of yarn is fed into the needle.

The periodically injected air throws the pile yarn onto the carpet front as it is fed. After each penetration of the hollow needle a loop is formed which height is determined by the feeding length. To produce a cut pile, a rotary blade is mounted behind the hollow needle, moving in a precise cycle. This cuts the pile on the carpet back when the hollow needle is in its most rearward position.

The hollow needle penetrates the back. As soon as it is in the forward position the air flow sets in, controlled through a valve. The cut pile yarn is then blown through the hollow needle like an uncut yarn.

The needle length and delivery wheel are matched so that one obtains two equally long pile loop halves after each penetration. The needle is cut at an angle. This achieves a uniform stitch interval which depends on the yarn thickness. A tufting rule for yarn tunnel dia. 6mm is : 20 stitches per 10cm tufted line

The machine is pressed against the backingand the gun is activated by a switch. With steady guidance the gun moves due to the cyclic advance of the slanted needle in the direction of the traced pattern.

The machine can be set at any speed from 50 to 1,400 stitches/min. When one row of tufting is ready, one returns the gun by placing the front foot of the machine against the previous row of tufting. The back an forth movement produces superimposed rows of tufting, with the stitches closer or further, depending on the product quality desired.

 

THE PILE HEIGHTS

Various needle lengths with their feed wheels are supplied by the manufacturer of the machine. They are easily exchanged. One can then obtain the most various pile heights (equal sides). There are needles and feed wheels for 16 – 74 mm pile heights.

UNEQUAL PILE HEIGHTS

If one uses a needle for 16mm pile height together with a feed wheel for 45mm pile height, one obtains one side with 16mm length and the other with 74mm. Many variations are possible with the exchangeable parts.

LOOP PILE

If one removes the cutting tool, one obtains a loop pile in the same length. The manufacturer does recommend a specially designed loop pile gun, since constant conversion is not only bad for the gun, but the lost production time is uneconomical in the long run.

YARN COUNT

There are presently conversion kits available with needles of inside diameters of 4mm and 6mm. With the 6mm needle, yarns of nm 0.25 or several thin yarns plied together can be processed. It is also possible to process thin yarn singly with this needle.

PILE MATERIAL

With the hand tufting machine wool, synthetics, cotton, silk, jute etc. can be processed especially recommend pure wool yarns, since this prolongs the life of the blades in particular.

CARPET BASE (BACKING)

The base material may consist of the most various wovens. Today the following are used

— cotton in various interlacings, eg. Panama, linen, twill, warp/filling about 60/60

— polyester of spun yarns polyester ribbon

— jute fabric in various interlacings

The carrier fabric must be so chosen that

1. the hollow needle easily pierces it
2. the dimensional stability is not lost
3. it is rot resistance

THE FRAME

For vertical work a frame is used which is shop built. You will find a plan in the tufting gun manual.

The frame consists of 4 bars with nail boards such as used by carpet installers, i.e. with nails driven through at an angle, fastened to them. The carrier is quickly framed when these nail boards are attached.

One must take care that the fabric is stretched straight and with the necessary tension. With some practice one obtains the correct tension without much effort.

A frame construction based on different rolls for guiding the primary backing is possible. The ready tufted and glued carpet is rolled on the upper roll. For the width stretching of the backing nailboards are used.

Stretching Primary backing cloth to tufting frame then drawing out design prior to hand tufting

 

Hand Tufting using Tufting Gun VML 16 by Hofmann then applying Latex to finished rug.

Latexing Shearing and Carving of handtufted rugs and carpets