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hikinglaserscreed · 4 years

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How to choose a concrete laser screed machine

With the development of the modern economy, with the tremendous progress of the Chinese concrete industries and with the improvement of the modern construction standard, the floor industry has also made a great progress. But the continuous increase of labor costs has obstructed the development of the floor industry, so replacing human labors with mechanization is the developing direction of the basic floor construction in the future, and now I will introduce you some information about how to choose the right concrete laser screed as follows:

1.Firstly, you should check the power configurations, and high power configurations are not always good

And when we come to pick out and purchase laser screed, we often fall into a trap, namely, we may consider that higher engine power is always better, but the fact is just the opposite. Compared with other laser screeds, the HIKING lasers screeds have adopted a lightweight and compact design, so its weight and its net weight has reduced a lot, and it has also adopted a high-end engine, which can keep two 1000 watts servo motors operating simultaneously without causing an overloading problem, and it has also adopted high power servo-driven motors and large torque gear reducers, thus it can have a higher walking speed and higher efficiency during the transfer.

2.Secondly, you need to check the making materials of the laser screed head, which is directly related to the screeding effect and the service life of this equipment.

For the material of the laser screed, it shall be very wear-resisting and indeformable. HIKING machinery has adopted the T6 high-silicon aluminum alloy as its manufacturing material, which is much more wear-resistant than the common aluminum alloy produced by other manufacturers, so the service life of its screed head is more than twice the length of other screed heads produced by common aluminum alloy materials, so for this kind of machinery which needs long-time service life, we should not buy cheap products made by nondurable materials, because finally the loss will outweigh the gain.

3.Thirdly, you need to check the vibration motors in the screed board, which plays a decisive role in the construction efficiency and the compactness of the concrete.

In the current market, the exciting force of vibration motors produced by other manufacturers is 500N in general, even the exciting force of the four-wheeled laser screed is just 800N. While the exciting force of the two-wheeled laser screed produced by the HIKING machinery company has already reached 2000N, which equals to 200KG and is 4 times as high as other manufacturers’ products, and because that general manufacturer can not effectively solve the problem of vibration in the machine body, the concrete screeding and compaction effects of our company’s products in unit time are much better than other manufacturers, thus a high efficiency and high quality project can be assured.

4.Fourthly, you need to check the electrical apparatus control system and to see if it has a good plug and play performance and if it has multiple options and modes to conduct the construction operation.

The HIKING concrete laser screed has adopted the PLC controlling mode, and its components and parts have the plug-and-play capability, while other manufacturers usually adopt the single-chip microcomputer control system, whose advantage lies in its small size, but it can not make its damageable components have the plug-and-play capability, so the after-sales service workers must go to the site to conduct the maintenance works, so a delayed construction caused by a shortage of time may occur. And for our products, you have multiple options and can choose many modes to conduct the construction operation, and push-button operation and touch screen operation are both okay for it, thus the construction efficiency can be greatly improved.

5.Fifthly, you need to check if the fully hydraulic-driven system has outrun the electric-driven system.

According to the types of products, they can be divided into the hydraulic-driven system, the electric-driven system and the semi-hydraulic-driven system, and because that they have a wide variety of products in different brands, their prices are quite different from each other too. Let’s take one branded product imported from America as an example, it can be regarded as a four-wheeled laser screed with an authentic entirely-hydraulic-driven system, but when we come to the cost performance, its super-high prices have make it lose its competing advantage. So in terms of the currently practical situation of the Chinese domestic market, many clients are more inclined to purchase the homemade four-wheeled laser screeds which have a higher cost performance. The laser screeds produced by the HIKING machinery company are equipped with a fully-hydraulic-driven system, and this laser screeds have adopted the four-wheeled-independently-driving hydraulic motors, and it has also adopted a steering and driving system which is controlled by proportional valves, thus a more stable construction can be assured, and the balance of the screed heads are controlled by the hydraulic cylinders, so all the advantages mentioned above have contributed to its handy operating system, higher construction efficiency and longer service life.

If you want to buy the laser screed machine you can check: Laser screed for sale to find your need.

This article from https://www.hkfloormach.com/knowledge-of-laser-screed/how-to-choose-a-laser-screed/

#laser screed machine

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journalmaterialscience-blog · 5 years

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4D Printing with Sequentially Controlled Morphing Abstract Sequentially controlled morphing (or folding/unfolding) has been a hot research topic for some years. With the additional feature of shape switching, 3D printing has been extended to 4D printing recently to significantly widen the potential application area. In technical terms, there are a few approaches to achieve 4D printing. In this paper, based the concept of multiple stable structure, we demonstrate how to achieve sequentially controlled morphing in 3D printed structures. We show that, the morphing sequence can be determined in the early design stage. Furthermore, utilizing the shape memory effect, we can even change the morphing sequence after the structure is 3D printed. Keywords: 4D printing; 3D printing; Reversible morphing; Sequential switching; Shape memory polymer Go to Introduction With the additional dimension of shape evolution against time, 3D printing has been extended into 4D printing, and the originally proposed concept of 4D printing and the underlying technologies to achieve 4D printing have been continuously modified [1-3]. One of the techniques currently under development is based the shape memory effect [4-6]. The shape memory effect refers to an interesting phenomenon that a piece of severely pre-deformed material recovers its original shape, but only at the presence of a right stimulus. Materials with such a capability are known as shape memory material [7-10]. Typical stimuli to trigger the shape memory effect include temperature (including both heating and cooling), chemical (including water and change in pH value) and light, etc [8-12]. Since most of polymers, including many conventional and newly available engineering polymers, are intrinsically have the heat/chemo-responsive shape memory effect [13], 3D printed polymeric items are inherently with the function of reconfiguration (morphing). In Figure 1, a piece of 3D printed (by Maker both) snake can be deformed easily at above its glass transition temperature (around 70 °C) into a shape. After cooling back to the room temperature (about 22 °C) and releasing the applied constraint, the temporary shape is largely maintained. Only upon heating to above the glass transition temperature again, the free-standing snake recovers its original shape. There are two processes involved in this cycle, one is to fix the temporary shape and is called programming, and the other is the recovery process. The material used for this snake is standard 1.75mm diameter poly (lactic acid) (PLA) filament. Since PLA is rather brittle at room temperature, the snake is relatively rigid and brittle and we cannot bend it too much at room temperature. Click here to view Large Figure 1 Same PLA filament is used to 3D print (Makerbot) a spiral spring as presented in Figure 2. The spring is able to be flattened after heating in hot water. Full shape recovery is observed when it is placed inside the hot water again. As compared with above mentioned snake, the flexibility of this spring is very much improved due to a kind of “structural design”. Hence, utilizing the heat-responsive shape memory effect, the same 3D printed spring may be programmed to instantly become an extension spring or a compression spring whenever needed, provided it is not over-heated to 95 °C or above. Over-heating of this PLA induces further crystallization. Consequently, the material becomes rigid at high temperatures as well and therefore it becomes difficult to effectively fix the temporary shape. Click here to view Large Figure 2 Above two examples clearly demonstrate the feasibility to have the morphing feature in 3D printed polymeric items. Despite of the achievement of morphing via the shape memory effect, programming is always required to fix the temporary shape before each cycle. This may not be convenient in some engineering applications. Sequentially controlled morphing (origami) is highly in demand in many applications, such as active assembly and disassembly, folding/unfolding of structures, and deployment and retraction of medical devices [14-19]. 3D printed sequential self-folding polymeric structures have been reported [5]. To avoid the un-convenience in programming and also high requirements in, e.g., design and 3D printing with multiple materials, for sequentially controlled morphing, we propose a simple way to achieve highly repeatable folding/unfolding using only one commercial filament. Essentially, this is an extension of the concept of bi-stable structures into multiple stable structures [2,20,21]. Since every individual shape is mechanically stable, upon loading/unloading, sequentially controlled morphing is guaranteed. Go to Flexible filament for 3D Printing Instead of using normal PLA filament in current 3D printing, which is brittle at room temperature, 1.75mm diameter Flexible filament from Shenzhen Esun Industrial Co. Ltd, China, was used for 3D printing via Makerbot. Differential scanning calorimetry test was conducted at a heating/cooling speed of 10 °C/min to identify its glass transition temperature as about 70 °C (Figure 3). The material does not have the crystallization problem (as that in normal PLA) even upon heating to 120 °C. Click here to view Large Figure 3 The stress vs. strain relationship at room temperature (about 22 °C) of the as-received filament was characterized by cyclic uniaxial tensile test to 5%, 10% and 15% strains in ascend order at a strain rate of10-3/s using an Instron 5569 with a load cell of 500N. The result is plotted in Figure 4. Herein, the stress and strain mentioned in this study are meant for engineering stress and engineering strain. The material is not fractured even being stretched to 15%, although significant residual strain is observed if it is over stretched. Based on the slope in the early unloading stage, the Young’s modulus (E) of the material can be determined as about 480MPa. A bi-stable structure was designed and 3D printed using this filament (Figure 5a). Upon compressing in the vertical direction, the as-printed shape switches to the other stable shape (Figure 5b). Subsequently, upon stretching in the vertical direction, the bi-stable structure switches back to the asprinted shape (Figure 5a). This reversible switching process can be repeated again and again as long as the involved maximum strain is well controlled in the design stage. Click here to view Large Figure 4 Click here to view Large Figure 5 Fundamentally, this type of structure is also known as a compliant structure, in which there is no conventional hinge at all, so that such a structure is just right for 3D printing. The shape memory effect and long-term stability of this material after 3D printing were investigated in this study. In Figure 6 (left), two identical Chinese words (meaning monkey) are 3D printed using this filament. The right piece is heated in boiling water and then its bottom part was bent to fix a temporary shape. Subsequently, there are left in air at room temperature for about two months. Unlike many currently used 3D printing materials, in particular those using UV light for curing, relaxation/creeping is virtually un-detectable in this material Figure 6 (middle). However, upon heating in hot water again, the programmed word returns back to its original shape Figure 6 (right). Thus, its excellent shape memory effect and long-term stability are confirmed. Click here to view Large Figure 6 Go to Design for Sequentially Reversible Multiple Stable Structures A commercial software, namely ABAQUS, is used for simulation via the finite element method (FEM) of the model with the potential for multiple stable shapes as shown in Figure 7a. The structure with a thickness of 10mmis supposed to be stretched (extension) and then compressed (compression) in the horizontal direction as indicated by two arrows. Essentially, there are three individual units from left to right in this structure. Each of them consists of an easy to buckle arch structure formed by two straight elements. The weakened end areas in each element serve as hinges. Due to symmetry, only half of the model as presented in Figure 7b (with major dimensions indicated) is used in current analysis. Click here to view Large Figure 7 It is obvious that with different geometrical dimensions, each unit may have a different buckling load, and thus to achieve sequentially controlled morphing in this multiple stable structure upon folding/unfolding. Figure 8a reveals the applied boundary conditions (in 3D) in the conducted simulation. The displacement at Ux=50 (as indicated) is controlled to simulate the process of extension/compression. Figure 8b shows the 2D mesh for FEM analysis. 8-noded hexahedral (brick) elements with reduced integration (C3D8R) are used to avoid the shear locking effect [22]. Click here to view Large Figure 8a Click here to view Large Figure 8 Since the actual filling ratio in later on 3D printing of the prototype is selected to be 70%, the Young’s modulus E used in current simulation is selected to be 350MPa and 0.35 is used for the Poisson ratio of this polymer for simplicity. The evolution in morphing of the model in cyclic extension/compression is captured by the FEM simulation. Figure 9 presents the shapes right before three sequential buckling events upon extension. Sequential buckling from the left unit toward the right unit is observed. The distributions of von Mises stress and the maximum principal strain around the hinges corresponding to the instants revealed in Figure 9 are plotted in Figure 10. The propagation of high stress and high strain from the pair of hinges in the left unit toward the pair of hinges in the right unit confirms the underlying mechanism behind sequential buckling from the left unit toward the right unit. Click here to view Large Figure 9 Click here to view Large Figure 10 Figure 11 reveals the force vs. displacement relationship in one full loading/unloading cycle. It is confirmed that upon extension, buckling starts from the left unit and propagates toward the right unit, while upon compression, buckling (opposite direction) follows exactly the same sequence as that in extension due to the difference in buckling load in each unit. A close-look reveals that the unit with a higher buckling load in extension requires a higher compression load for buckling as well, although the magnitude of buckling load in compression is less than that in extension for the same unit. Click here to view Large Figure 11 As demonstrated above, the FEM does provide a convenient approach to design a multiple stable structure with sequentially well controlled morphing function. Therefore, we can design different structures, which may be difficult to be fabricated using conventional manufacturing techniques, but can be 3D printed using a right material, with a prescribed folding/unfolding sequence required in a particular application. Go to 3D Printed Structures, Experimental Results and Comparison Using the 1.75mm diameter Flexible filament mentioned above, two prototypes with different configurations are 3D printed with 70% filling ratio using Makerbot. Subsequently, the prototypes were tested under cyclic loading/unloading (extension/compression) as they are initially designed for controlled sequential morphing using an Instron 5569 with a load cell of 500N at a speed of 1mm/s. In the experiments, the prototypes are placed vertically and fixed by top and bottom two clamps for extension/contraction along the vertical direction. In addition to record the applied force and corresponding displacement, a video camera is used to monitor the shape change in real time. The obtained force vs. displacement curves for Design I, which is the model for FEM simulation in Section 3, in four continuous cycles are plotted in Figure 12, together with photos (extracted from the video clip) right after each buckling event (the exact occasion is marked in the force vs. displacement curve, and since the corresponding force is zero, the free-standing structure is indeed mechanically stable). As we can see, in general, the resulted curves in all four cycles are well overlapped, which confirms high repeatability of the prototype upon mechanical cycling. Within a couple of limited areas, the curve of the 1st cycle is slightly away from the rest, which should be the result of additional initial boundary condition caused by the clampers. Click here to view Large Figure 12 The experimental result of the 4th cycle, which can be considered as a typical cycle, is compared with the simulation from (Figure 11) in Figure 13. Since buckling is a phenomenon of instability, the influence of imperfection (including those caused by 3D printing) could be significant. As such, it is very hard to precisely repeat the experimental result without a full consideration of these imperfections in simulation. Hence, according to Figure 13, we may say that our prediction (via FEM simulation) is able to catch not only the general trend, but also most of the major features observed in the experiments. Click here to view Large Figure 13 Figure14 presents the result of Design II, in which the sequence of buckling is initially designed as following: Click here to view Large Figure 14 Upon extension, the middle unit buckles first, then the left (bottom) unit buckles and finally buckling occurs in the right (top) unit. Upon compression, the left (bottom) unit buckles first, then the right (top) unit buckles and finally buckling occurs in the middle unit. So that this is different from the sequence of Design I, from the left (bottom) unit to the middle unit to the right (top) unit in both extension and compression. However, same as in Design I, good repeatability is observed, in particular in the last three cycles. Since the polymer used in current 3D printing has good heating-responsive shape memory effect, we heat the original shape of Design I to above its glass transition temperature and then extended the middle unit for buckling. After cooling back to room temperature, a modified Design I is resulted. Subsequently, we compress the middle unit for buckling again, so that the current shape of modified Design I looks to be identical to the original Design I, i.e., all units are in compacted state. Snapshot of one typical cyclic extension/compression test presented in Figure 15(a-f) reveals that the buckling sequence of the modified Design I is different from that of the original Design I, i.e., Click here to view Large Figure 15 Upon extension: the middle unit buckles first, then the left (bottom) unit and finally the right (top) unit. Upon compression: the left (bottom) unit buckles first, then the middle unit and finally the right (top) unit. In Figure 16, we compare typical force vs. displacement curves of the original Design I and modified Design I. Re-set the shape via the shape memory effect indeed changes the buckling force of the middle unit, and thus correspondingly, the buckling sequence is changed. The original buckling force for the middleunit is about 6N for extension, and 4N for compression. After modification, the buckling force for the middle unit is about 4N for extension, and 5N for compression. Click here to view Large Figure 16 Go to Conclusion In this paper, we demonstrate the feasibility to achieve sequentially controlled morphing in 3D printed multiple stable structures via two approaches, namely structural design and modification of the printed structure via the shape memory effect. Thus, different morphing or folding/unfolding sequence can be realized in the early design stage and/or later on after the structure is printed. Although the model investigated here is essentially 2D, which can be easily fabricated by many conventional manufacturing methods, such as injection molding, we believe that the basic concept proposed here can be extended to 3D structures, including those structures that are difficult to be fabricated by conventional manufacturing techniques. For more Open Access Journals in Juniper Publishers please click on: https://juniperpublishers.com/ for more details click on the juniper publishers material science

#Juniper Publishers #juniper publishers group #material science #composite materials

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suggestionsofthecaribbean · 6 years

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The Afterlife: Jack and fifty shades of loneliness

That’s so sad alexa play despacito

Featuring @jacksparrowsuggestion

Jack opens his eyes.

It takes a while for them to adjust to the dimly lit room, just long enough for him to notice how light he is. It feels like when you’re in the middle of falling, though with the notable lack of any movement. He looks down and sees his bare feet, almost a decimeter above the wooden floor.

That’s probably the reason for that odd feeling, he decides and tries to take a step. For some reason he only manages to slowly fall forward. It’s almost like moving in water.

Jack looks around. He’s surrounded by shelves on all sides, filled with heavy books in an absurd amount of different colors and shapes. The second the thought of inspecting them enters his mind he feels a…tug. It’s like a stream is moving him and he lets himself get pushed along until he finally stops in front of one of the shelves. Right in front of his eyes is a dark red book. The words Sparrow, Jack are scribbled on its back in a messy, all too familiar handwriting. His handwriting. Jack lets his hand wander to the book and carefully touches it. He accidentally brushes against another book and feels his fingertips pass through it.

So that’s new.

No books except the one with his name on it offer any resistance. His hands just pass through them as he grabs the red book. He opens it and vaguely notices himself floating upwards as he sits crosslegged in the middle of the air.

The first few pages are empty. The next are bent, like they’ve been laying in the rain for hours, and the first paragraphs of text are barely readable. The first sentence Jack can properly make out is ’It was storming’. Jack skims through the next few pages, not really reading anything. Here and there he’ll notice names he remember and places he’s been, but most of all he pays mind to how the actual pages look. Most are damaged by water in some way. Others are paled by sunlight. More than a few are stained with blood.

By the time he gets to the last few pages Jack starts to notice how high up he is. He can barely see the floor anymore, but when he looks up he can’t see the roof either. The building must be huge, he thinks as he carefully turns pages to the last one.

It’s completely ruined. Soaked with sea water, the ink smudged out in a mass of grey. Jack is almost hesitant to touch it. It feels wrong, for some reason. Like he’s doing something forbidden, even though he’s never had a problem with that before. There’s something in the middle of all the grey. A figure that Jack traces. When he takes his fingers off the page they’re stained with ink.

He turns the page, almost as if in a trance, then puts his finger to the inside of the cover. Slowly, he writes the words ’To be continued’

And then he falls.

Jack blinked and stared at the sign in front of him.

He could have sworn he’d just been falling, but evidently that was not the case. Or was it? He looked up at a dark sky. Too dark. Like ink.

Jack looked back, but only saw a road stretching out as far as he could see, which was really only just past the lamp hanging above him. It was probably there to illuminate the sign.

’H34V3NLIE MÅLL

0000

00000000

000000000000

0000000000000000

000000

000000’

Jack had to admit that he had a hard time believing the ’h34v3nlie måll’ (whatever that was) was as far away as the ridiculous amount of zeroes indicated. He looked back at the road leading away from the sign. The most notable things around were a bunch of sad-looking cacti and Jack quickly decided that whatever a ’h34v3nlie måll’ was it was better than death by boredom.

A shudder ran through him at the thought of death, but he quickly shrugged it off and tried to take a step forward. Instead came the weird feeling of being pushed on by a stream again and Jack quickly found that he could control how fast he went and when he wanted to stop. He would probably have cared more if it wasn’t for how weird everything else was. His unusual way of moving didn’t really feel out of place compared to that.

If time passed while Jack followed the road it sure didn’t look like it. The sky was still the same inky black when he arrived at another sign, hanging above the road. It was lit up by sharp, bright colors that stood out against the dark.

’H34V3NLIE MÅLL

500N’

Soon sounded uplifting, even if Jack didn’t know how soon ’soon’ was. As he stepped under the sign he noticed a faint glow by the horizon. Almost like a sunrise, but smaller. As he began floating towards it he heard a melody in the distance. Only it was the wrong distance. It came from behind him, but grew stronger the closer he got to the light, like something was following him. And gaining on him. Jack quickened his pace.

The source of the light turned out to be a huge building, bigger than most mansions he’d seen. The road led straight to the entrance, where a final sign stood.

’H-3-4-V-3-N-L-I—E— -M-Å- - Å-L-L

W’

Jack came to the brilliant conclusion that the building must be the oh so spoken about ’h34v3nlie måll’. The music sounded like it was about ten meters behind him now. He couldn’t make out any of the words, but it sounded vaguely like Spanish. Deciding that it wouldn’t be any use standing around outside, Jack headed into the building. The doors opened by themselves, which was weird, but not as weird as just how much of the building was made up off glass. Jack had never seen so much glass in his life, at least not in the same place, and he was in the middle of admiring it and wondering if maybe he could steal a little when a voice rang through the building.

”WELCOME”

Or well, voice wasn’t quite the right word for it. It was more like several voices in one, and they all spoke in different tones and accents. Jack looked around to see if he’d be able to find the source of it, but only managed to catch a glimpse of a shadow that quickly slipped out of view. It continued to do so as Jack tried to catch it, so in the end he settled for simply having it in the corner of his eye.

”Who’s there?” He asked.

”I AM ALEXA. WELCOME TO THE H34V3NLIE MÅLL. HEAVEN IS A PLACE ON- HEAVEN”

The sentence sounded pieced together. Like Alexa, whoever they were, had been cut off after ’on’ when they’d meant to say something else and the last ’heaven’ was just the same as the first. Like a recording that had started over.

”What is this place?”

”THE H34V3NLIE MÅLL IS THE BEST PLACE TO SPEND YOUR WEEKEND, AFTERNOON OR AFTERLIFE. THIRTEEN STARS ON TRIPADVISOR”

”Afterlife?”

”’AFTERLIFE’ IS, AS THE NAME SUGGESTS, A TERM REFERRING TO A LIFE AFTER DEATH. IT IS UNCLEAR WHEN IT WAS FIRST USED BUT-”

Jack’s phone started beeping (which was odd because he could have sworn he’d turned the sound off that morning) in his pocket. When he reached for it he realized that he wasn’t wearing his own clothes. They’d been replaced with a pair of pants in a coarse, light blue material and a short-sleeved shirt that had been cut at his ribs. Jack didn’t have time to wonder about that too much though, seeing as the beeping was a news notification.

’@jacksparrowsuggestion found dead in Tortuga’

Oh.

That explained a lot.

’I AM ALEXA. WELCOME TO THE AFTERLIFE’ Alexa said.

Somehow, Jack doubted he was going to enjoy his stay.

#potcsuggestions

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