Glass Fiber &Nbsp; Good Performance Should Also Be Used Smoothly.

Fabric structure and knitted properties

Research

Plain weft stitch is one of the most basic structures in knitted fabric structure. It is also one of the most commonly used structures for weft knitted structures. And it can clearly observe the positive and negative sides of fabrics in the study of fabric geometry. It has become the first choice for knitting scholars at home and abroad.

Rib fabric is the basic structure of double faced weft knitted fabric. It is formed by the vertical alignment of the front coil and the reverse line.

The structure of the tissue has good lateral extension.

Tubular fabric is a kind of three-dimensional fabric. It has different types of knitted fabrics with different organizational structure, and there are many types of tubular fabrics that can be knitted on flat knitting machines (for example, cylindrical fabrics with flat stitch, weft insertion and spacing).

Fiberglass tubular fabric can be made of several types of cylindrical composite materials through several layers of compounding, which has high strength because there is no joint around the cheese.

Its water resistance is theoretically higher than that of a circular tube made of woven fabric with the same thickness and the same specification.

The rib air layer and border weaving organization belong to the color change organization.

The rib air layer is also known as the "Milan Nuo" organization.

It is made of rib stitch and single sided stitch. The pverse elongation of the fabric is smaller than that of rib stitch, and its dimensional stability is better. This is because a complete organization of its fabric needs to be formed by three braiding, two stitches of tissue stitches and rows of rib stitches.

Weave the structure of the ring with a set of rings to study the properties of the different coil structures, and select the whole border knitting organization on the two needle beds alternately collecting ring, or the border knitting organization, also called the double fish scale fabric and the double treasure fabric.

　　實(shí)踐證明，只要在編織時(shí)綜合考慮彎紗深度、牽拉力、給紗張力等條件的影響，選取適當(dāng)參數(shù)，可編織出較理想的玻璃纖維緯平針織物;在滿針羅紋編織時(shí)，彎紗深度、牽拉力以及給紗張力等參數(shù)要求更為嚴(yán)格，編織也較困難;筒狀織物由于要用兩針床進(jìn)行編織，為了使織物均勻，要盡量使針床的間距與針距保持一致;羅紋與單面平針的線圈不一樣，最終形成的織物表面會(huì)有凹凸條紋，所以在羅紋空氣層織物編織時(shí)要注意密度的控制，使密度適當(dāng)，否則會(huì)使織物的橫條紋現(xiàn)象很明顯，并使間隔不規(guī)則;編織畦編織物時(shí)要注意根據(jù)集圈時(shí)機(jī)頭的運(yùn)動(dòng)方向，來(lái)配置兩針床的織針，以防止邊針脫針而影響編織。

Control of factors affecting normal knitting

Influence

When knitting glass fiber knitted fabric on flat knitting machine, the depth of the bent yarn has great influence on weaving.

The bending yarn depth is too large, the coil is easy to get rid of needles, the difficulty of weaving is increased, the depth of the yarn is too small, the contact between the coil and the machine is very tight, and the friction is large, which also brings difficulties to the knitting and even damages the knitting needles. Through repeated trial weaving, it is found that the suitable depth of bending yarn is 3.5~4.5.

When the depth of the yarn is suitable, the weaving is more successful and the cloth quality is better.

From the Euler formula, it can be concluded that when the depth of the yarn is fixed, the maximum bending tension is directly proportional to the yarn tension, the friction coefficient between the yarn and the ring forming machine and the sum of the surrounding angles.

Therefore, in the case of smooth weaving, yarn tension should be reduced as far as possible.

The yarn tension of the hand flat knitting machine is not easy to be controlled quantitatively. In the knitting process of this topic, yarn is penetrated from the guide yarn, and the negative feeding mode is adopted. The size of the yarn tension is changed by adjusting the disc tension device.

After repeated trial weaving, it is found that under the condition that the take-up spring can fully absorb the residual lines generated by the reversing of the head, the tension of the disc tension device is adjusted to the minimum, the braiding is most successful and the fabric effect is better.

In the actual knitting process of flat knitting machine, the value of traction force has great influence on fabric.

Pulling can play two important roles. First, the newly formed coil is pulled to the back of the needle to prepare for the next horizontal knitting. Two, at the same time, it is ensured that the old coil can smoothly slide to the needle bar when the needle is removed, and the fabric does not rise along with the knitting needle, so that the knitting can be carried out normally.

In the knitting process, the pulling force can not be too large.

And the pulling force should be uniform.

During the actual operation, if the yarn does not float along with the needle rising, choose the smallest pulling force.

Through repeated experiments, the moderate pulling force of each tissue during weaving is obtained.

It can be seen that the single ply fabric has less traction than the double-layer fabric, and the pulling force increases in the 4 knitting processes of the full knitted rib fabric, the rib air fabric, the tubular fabric and the border fabric.

Generally speaking, the slow or medium speed of the machine can make the knitting work smoothly. For the 5 kinds of fabric knitted with one side flat needle, full needle rib, tubular fabric, rib air layer and border knitting fabric, the speed of the head should be slowed down in turn.

In weaving, the speed of the machine head is moderate and slow, and even as far as possible, so as to reduce fiber damage and ensure fabric evenness.

The different fabric structure will affect the properties of composite materials, and will also affect the difficulty of weaving.

Border knitting is not easy to weave with respect to plain needle.

When knitting, it is necessary to make the spacing between the needle beds as far as possible, so as to weave better fabrics.

Relationship between strength damage rate and fabric weave

By analyzing and discussing the damage degree of glass fiber yarns in different weft knitted fabrics, it can quantitatively evaluate the knitability of glass fiber yarns.

Basic conditions of braided specimens

The raw materials for sample weaving are all made of alkali free continuous glass filament yarn produced by Henan Luoyang crystal weft Glass Fiber Co., Ltd. its specifications are: monofilament diameter is 9 m, yarn is two strands, single yarn yarn density is 34tex, twist is 60 twist / rice, twist direction is S.

Machine number: taking into account the fineness of the yarn and its machine number, the domestic hand-held flat knitting machine (E10 without a presser) is chosen.

Organization structure: after trial weaving and analysis in front, we select 4 typical organizational structures: single sided flat stitch, full stitch rib, rib air layer and border knitting.

Process parameters: the size of the sample is selected to be 15cm * 15cm. Apart from the length of the coil (that is, the depth of the yarn), each specimen remains unchanged, such as pulling force, yarn tension, head speed and other parameters, and meets the most suitable technological conditions.

The selection of the length of the coil is to adjust the looping triangle to achieve the minimum coil length, the depth of the yarn to be knitted, the length of the coil to be braided, and to continuously increase the coil length until the fabric can not be braided normally, and the fabric with different coil length (i.e. the depth of the bending yarn) is woven.

The increase of the general coil length is about the 3 scale of the circle triangle dial.

Quantitative analysis of injury degree

The damage degree of glass fiber yarns is quantitatively evaluated by using the yarn strength damage method, that is, the damage degree of the yarn is determined by the tensile breaking strength of the unwoven yarns and the percentage of tensile breaking strength of the yarns removed from the fabric after weaving.

According to many experimental observations, the fiber damage caused by the dispersion is very small compared with the fiber damage caused by weaving, so it has little effect on the final result.

Experiment and result analysis

The experimental instrument is made of YG061 electronic single yarn strength tester made by Laizhou Electronic Instrument Co., Ltd., and the yarn breaking strength before and after braiding of glass fiber is tested.

The test steps are divided into two steps: sampling and instrument operation.

Sampling: non woven continuous glass filament yarn produced by unwoven Henan Luoyang Jingwei Glass Fiber Co., Ltd., its specifications are: the diameter of the monofilament is 9 m, the original silk density is 34tex, the yarn linear density is 34 2tex, the twist is 60 twist / rice, and the twist is S.

Take woven samples (flat needle, rib air layer, full needle and border stitch four tissue samples) and disassemble them. Pay attention to the utmost care when breaking up, minimize the damage caused by the glass fiber yarn in the process of breaking up, and each organization has a small amount of disassembly each time.

Instrument operation: according to the operation steps of the YG061 electronic single yarn strength tester, the experiment is carried out step by step, and the usual value of pre tension selection fiber strength test is 10cN~14cN.

The variation trend of each curve is consistent, that is, within a certain range of coil length, there is a minimum point of strength damage in the 4 fabric tissues, which is larger than or smaller than the coil length range at this time, and the strength damage of yarn has increased.

This is the overall trend of the effect of coil length on the strength damage rate of yarns.

It is not difficult to find that although the fiber damage in the 3 tissues is consistent with the trend of the coil length, the strength damage rate of each tissue is different. The fiber damage rate of flat needle tissue is lower than that of full needle rib, rib air layer and border knitting tissue.

The lowest damage rates of full needle rib, rib air layer and border knitting tissue were 31.61%, 33.41% and 37.34% respectively, while flat needles were about 27.38%, which was closely related to the fabric structure.

Generally speaking, if there is no special requirement for fabric weave, a more suitable tissue, such as plain stitch, can also be used to control the damage rate in a very ideal range.

The depth of bent yarn has a direct effect on the strength damage rate.

First, the flexural rigidity and friction coefficient of fiberglass yarns are much higher than those of ordinary yarns.

When weaving glass fiber yarns on the hand flat knitting machine, try to make the surface of the knitted components smooth and smooth, thereby reducing the friction between the glass fiber yarn and its surface and reducing the damage of the glass fiber yarn.

The two is to ensure smooth weaving and start with ordinary yarns.

The three is to control the depth of the yarn in a suitable range to reduce the tension of the glass fiber yarns. In this paper, the minimum yarn tension is guaranteed when the take-up spring can fully absorb the residual lines generated by the reversing of the head.

At the same time, in order to smooth out the loop and not to break the yarn due to excessive traction, the pulling force must be increased properly, but not too large.

The four is the analysis of the strength damage rate of the yarn made of glass fiber yarns after weaving different tissues. The results show that the strength damage rate of glass fiber yarns is closely related to the depth of the yarn (i.e. the length of the coils), and there is an optimum parameter value.

Plain knitted fabric has the lowest fiber damage rate, and it is relatively easy to achieve the control of fiber damage rate in a reasonable range. It is an ideal organizational structure.

The air layer of full needle rib and rib is slightly higher than that of plain needle. Because of the different requirements for the bending yarn of the border knitting organization at the same time, the damage of the glass fiber yarn is more serious. When there is no special requirement for the organization, the flat knitted fabric is often chosen.

Five, it is found that woven glass fiber yarn is more likely to cause wear and tear of machine parts such as circle triangles and knitting needles by observing the forming of ring forming machines. This also proves that weaving of glass fiber yarns is more difficult.

The six is the knitting of 5 kinds of knitted fabric, the flat needle is the most easy to weave, and it is gradually difficult to weave the order of the knitted fabric, the cylindrical fabric, the rib air layer fabric and the border braid.