Viewing blog posts in the Technical category.
And we can see why. Originally only seen in lateral filing systems, wide and deep drawers are now found in residential applications, especially kitchens. Commercial applications include display and storage for retail, catering, industrial and electronic and, of course, office files.
When selecting the slides for your wide drawer project be careful to read the manufacturer’s technical details. Maximum drawer widths should be given for each type of slide; this is most likely to be described in the load rating and testing descriptions. If the slide has been tested on a drawer of 450mm wide, then it may not work well on your 1m wide project.
The slide manufacturer should have tested each slide model to determine the maximum drawer width it will safely carry. Choosing slides based on the drawer width, as well as the load, is the best way to ensure good movement and reliable performance.
Drawer width is especially important in situations where the drawer box is wider than it is deep. This construction puts more stress on the drawer and slides, causing a halting movement and a wracking or side to side movement.
We would generally recommend that the slide length is equal to or slightly longer than the drawer width. We have some slide products that have been specifically tested for wider drawer applications.
Looser slide movements can accentuate this wracking. This is caused by greater freedom within the slide and the force applied to the slides when a drawer is opened or closed with an offset pull or push by the user.
We advise, where design restraints allow, that you use a central pull handle on wide drawers. Where two handles, or one very long handle exist, the temptation is to try and open the drawer from one side only. This puts a strain on the slides and will eventually lead to problems within the slide.
Inching or ball migration is a condition where the ball retainers in the slides move at different speeds and distances causing them to get out of sync with each other and with the slide members that they support.
Inching is a common problem with the design of ball bearing slides that all manufacturers have to deal with. Accuride works continually on the design of the ball track shape to keep this problem under control. It is important that each set of balls roll effectively in their tracks and that the movement between the members and the ball retainers is always kept at a 2:1 ratio.
We check and test the design of the ball track to maintain this finite shape and achieve a true single ball contact through the ball diameter so that true rotation of the ball bearings is realized.
It is always best to choose a slide that meets your drawer width requirements, even though the slide load rating may be greater than what is needed for the project.
If you’re not sure about any of the technical details then email a question.
Most ball bearing telescopic slides are designed to be mounted in pairs vertically, on the sides of drawers or the moving unit.
There are some slides that can be mounted flat beneath the moving unit.
If slides are mounted horizontally (flat mount) the load rating is decreased to approximately 25% of the vertical load rating. Some slides may have a lower or higher percentage.
Look at the individual product datasheets or in the e-catalogue for this symbol:
Linear slides such as the 1312 and 0115RS perform better when flat mounted because the moving member is fully supported on ball bearings at all times.
The DA0115RC uses re-circulating ball carriages and is ideally suited for this orientation of mounting; see the datasheet for details of load ratings.
Mounting slides in different configurations will affect performance and load rating and we always recommend that you test the slide in the intended application.
Accuride has many years of experience in designing, testing and using telescopic slides. From this experience we have learnt that some slide profiles are just not suited to being used in the horizontal plane (flat mounted).
Problems can arise with deflection, especially with heavy loads on longer lengths, and with interference between the slide components, which can cause sliding components to grind together where clearances are minimal.
Some ranges have been designed, for example, with minimal wrap on the intermediate member (IMM), or the shape of the outer member (OM) has a flatter shape allowing lateral movement when flat mounted.
These cross sections have no problem handling loads in vertical/side applications, but when used flat, the members and ball retainer could easily disengage from the mating members, or grind / rub together.
|Model||Side mounted max. kg*||Flat mounted max kg*|
|0115RC DA||see datasheet||see datasheet|
|0330 DS (80,000 cycles)||65||16.25|
|0330 DS (10,000 cycles)||80||20|
|2028 DS (80,000 cycles)||60||15|
|2028 DS (10,000 cycles)||65||16.25|
|4120 DA (10,000 cycles)||438||219|
|4120 DA (5,000 cycles)||550||275|
|5417 (80,000 cycles)||90||22.5|
|5417 (10,000 cycles)||100||25|
This is the maximum load that a pair of slides can carry, but only IF you mount them as instructed and don’t exceed their cycle rating. The stated load ratings are a gross load, so don’t forget to add the weight of the drawer construction materials to your calculations
‘Cycle rate’ is another term that we should explain. When slides are tested they are set up in a test rig with a drawer, or in their application environment, and ‘cycled’ in and out a number of times. One cycle = a complete open and close.
The cycle test is a dynamic load test. Different cycle rates are used depending on the type of slide and the expected application. For example, in applications for the Industrial and electronic market sector, the cycle rate will typically be between 2,000 and 10,000 cycles and for the furniture market sector, the cycle rate will typically be between 50,000 and 80,000 cycles.
All our products are subjected to a static load test at full extension of the sliding elements. The load applied will typically be at least twice that of the dynamic load test. This means the slide will have a 100% static safety factor in the extended position.
Deflection of the drawer and sliding element are measured during the dynamic test phase and this is correlated to the load and number of test cycles completed. Din 68 858 details the allowable percentage of the extension this deflection can be.
Accuride tests all of its standard slides in the same way so that you can compare ‘like for like’. Remember that the tests have been devised for the drawer and component together – there are no standard tests just for slides. If you have an application that is not a drawer – and Accuride slides can be found in many and varied types of applications – then we would recommend that you test the slides in your own situation.
When you look at a product page you will see that we give a load per length, state the cycle rate used for the test and the load rate where flat mounting is available.
The tests are conducted in our in-house laboratories, which are based in each of our design and manufacturing sites around the globe.
The slides are typically mounted 450mm apart and the load is placed with its centre of gravity in the centre of drawer. Measurements are taken and the test rig is then started and will run through the cycles, with further measurements and checks made along the way. As previously mentioned, we test furniture sector slides up to 80,000 cycles and industrial sector slides up to 10,000 cycles, but there are variations. Look at the datasheets for detailed information.
A wider drawer has a negative effect on slide performance and choosing the wrong slide can result in a side-to-side wracking movement that feels loose and unstable. Some of our slides are designed specifically for wider drawer applications and are therefore tested further apart. These are detailed in our product catalogue and website.
Our product is also subjected to slam open and slam shut test elements, which entail slamming the drawer / slide against the open and closed end stops. This test is carried out for 10 slams in both directions at a speed of between 1.25 and 1.85 m/sec, dependant upon the load applied.
Different applications may have their own set of standards for testing and we can accommodate customer requests.
Our general test standards come from a range of national and international sources, such as; BIFMA, ANSI, ISO, BS and Din, etc.
We can also set up tests for a customer’s project. Sometimes we may need to take the test out of house, for example, crash testing for automotive applications.
Things to consider before you select a ball bearing drawer slide, read more.
Customers need to be sure that the slides they buy will have a certain amount of resistance to corrosion. Part of our finish testing includes a salt spray chamber where slides are exposed to a 5% salt solution (similar to a salty fog) to test corrosion resistance.
The test procedures and parameters are standardized under national and international standards, such as ASTM B 117 and ISO 9227. These standards lay down the required information to carry out these tests; covering the test parameters, such as the temperature, the air pressure of the sprayed solution, the preparation of the spraying solution, including the Ph concentration, etc.
We have our own internal test laboratories and these include salt spray chambers. When we have a new product, we test each of the component parts as well as a complete assembly. These are placed in a chamber so that all parts are fully exposed to the sprayed solution. The solution must also be able to drain off the surfaces and not form pools.
After the required test period, the parts are dried and examined for traces of corrosion. The results are recorded on official test reports, which outline the test piece specification, the type of finish applied, the test standard used and the appearance of any corrosion.
Corrosion can range from none at all, through to white or red rust depending on the severity of the test and the finish used on the slide.
Minor white rust is a cosmetic effect and generally has no effect on the performance of the coating if the underlying zinc coating retains the specified coating thickness.
Accuride has three levels of corrosion resistance within our range of drawer slides, which include a resistance of 12 hours for the majority of our range, plus 96 hours and up to 500 hours for the high performance surface finishes.
Different coatings are used to achieve the standard and enhanced levels of corrosion resistance and these are applied to the electroplated zinc coat during the automated finishing process.
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