Saturday, June 27, 2009

CE Marking to EU Directives

When designing the machine for the customers in Europe, I have to make sure that the machine has full CE compliance.

By the way, what is CE?

I search for more details about CE and put them here for more understanding.

The CE marking is an acronym for the French "Conformité Européenne". By affixing the CE marking, the manufacturer, or in certain cases another legal person responsible for the product, asserts that the item meets all the essential "Health and Safety" requirements of the relevant European Directive(s) that provide for the CE marking. Examples of European Directives requiring CE marking include toy safety, machinery, low-voltage equipment, medical devices and electromagnetic compatibility.

CE Marking Procedure

The "New Approach" to conformity enables manufacturers to use what is called as "SELF DECLARATION" where the manufacturer himself declares conformity by signing the "Declaration of Conformity (DOC)" and then affixes the CE Mark on his product.


The following simple steps are involved
STEP 1: Identify Applicable "DIRECTIVES"
STEP2 : Identify Applicable "Conformity Assessment Module"
Although CE Marking follows the Self Declaration principle, depending upon product complexity and risk to human life, various conformity assesment module are prescribed:-
Module 'A' (Internal Production control).
Applicable for products falling under EMC and Low Voltage Directives. Manufacturer tests the product from third party. After compliance with the tests, his production process ensures continued conformance. He maintains "Technical Documentation" as a proof of compliance. There is No mandatory involvement of European Lab (i.e. Notified Body).
Module 'B' to 'H'
Mandatory involvement of European Lab is required which issues "Type Examination Certificate", certifies documentation (called "Techncal Construction File"(TCF) and carries out inspections.
STEP3 : Identify Applicable "Standard"
STEP4 : Test one sample of the productEither yourself or from test lab.
STEP5 : Compile "Technical Documentation"
STEP 6 : Sign the EC "Declaration of Conformity"
STEP 7 : Affix "CE Mark" on the product.

Source: http://en.wikipedia.org/wiki/CE_mark

There are 21 European "New Approach" Directives against which a wide range of products are required to be CE marked against before they are "placed on the market" in Europe. When placing the CE mark on the product the manufacturer or "his authorized representative in the European union" is declaring that the product complies with all applicable directives. The list of 21 applicable directives can be found on the European Commission website. The EU Directives are not themselves law as they are all taken into the the law of each member state. Whilst the directive and standards may be harmonized across Europe manufacturers still need to be aware of country specific requirements in safety standards, permitted frequency bands and other areas that might affect their product.

Some directives requirements are more onerous than others, but a general guide is that a manufacturer must

  • identify all directives applicable to their product
  • assess their product against the requirements of a directive - usually through a combination of technical argument and testing. Testing can be done in house by the manufacturer or by 3rd party specialist test laboratories
  • create a Technical File containing full details of the product and all assessments carried out to demonstrate compliance. This technical file becomes a living document and needs to be kept up-to-date as changes occur to the product or to the standards against which the product was assessed
  • depending on the directive there is an optional or mandatory requirement to have the Technical File assessed by a Notified Body
  • Draw up and sign a Declaration of Conformity and affix CE mark to the product and/or packaging

Charlie is a CE marking consultant at DheaniSulis Ltd who specialise in helping companies navigate their way through these product approval requirements in a timely and cost efficient manner.

Article Source: http://EzineArticles.com/?expert=Charlie_Blackham

Sunday, June 14, 2009

Sankyo AD Alpha Series - Dial Index

If you are looking for a strong indexing box for your dial application, you can have a look at Sankyo AD Alpha Series.

Apart from its product specifications, you'll find useful technical information regarding indexing drives.

Sankyo's AD/Alpha Series
features a low profile design cast iron housing with a ground pilot flange for mounting dial plates, hub less gears, or weldment fixtures. Above the indexing dial, a second dial mounting surface is stationary and hollow to allow air lines, wiring or bearings for a shaft to be routed through the tolerance bore. A globoidal cam rotates Sankyo made needle bearing type cam followers. Optimizing the cam follower diameter inherently maximizes torque transfer and extends the life hours due to fewer rotations with increased surface contact.


Multiple index periods offer continuous or on demand duty cycles with the indexing flange locking in position within 30 arc seconds during the dwell period. The output flange turret is mounted with top and bottom tapered bearings which supports large bending moments, maintain rigidity and reliability. These versatile units index in both directions, oscillate or perform non-patterned motions with a continuous lead cam using servo driven motors. Most units are driven with geared motors that are within the height of the index unit housing. There’s no need for spacers or burning a hole in the mounting plate to accommodate for drive height interference. An optional torque limiter safety clutch mounts between the index and indexing dial plate. Torque thresholds are easily adjusted without any disassembly and a proximity sensor detects overloads.

Timing cam packages are available with inexpensive photo beam sensors or proximity switches for wash down (IP67/NEMA-6/6P) applications. The AR/Alpha ServoDEX Series shares the same housing as the AD/Alpha series but uses a constant lead cam for programmable indexing stops with a servo motor drive. Non-patterned motions, oscillating, variable or continuous speeds can be programmed to suit your current application needs or reprogrammed for the future. Repetitive accuracy is within 30 arc seconds or 0.0014” per inch of radius.

Features
  • 2 to 32 incremental output stops, 1-dwell cam equals; 1-output stop to 1-input shaft revolution, 2-dwells for 16 to 32 stops
  • Dial diameters range from 280mm to 3600mm (1 to 12 feet) with second stationary dial mounting
  • 120° to 330° index periods with Sankyo modified sine or constant velocity (~50% CV) cam curves
  • Maximum 200 cycles per minute, bi-directional indexing, oscillating motions (non-pattern for servo driven AR/ServoDEX)
  • ±30 arcsec indexing accuracy (average ±9 arcsec), 30 arcsec repetitive, ±60 arcsec for 2-dwell cams for 16 to 32 stops
  • Painted cast iron housings are available in 8 standard sizes ranging from 70 to 450mm input to output shaft centers
  • Standard stationary hollow flange output with tolerance bore, available with optional torque limiting clutch
  • Index mounts in any position with right angle gearmotor mounting in 90° increments on either side of the index
  • Standard brushless dual voltage (230/460) gearmotors are UL & CE certified, brake motor or wash down optional
  • Variable frequency drive controller utilizes electronic braking and variable speed for gearmotors in 115-1ph, 230-1/3ph, 460-3ph volts, 50/60 Hz, UL & CE certified
  • Stop/start frequency up to 60~90 per minute (output load/reducer dependant), clutch brake or servo drives are available
  • Standard IP50 photo eye timing cam sensor package supplies dial “in position” signal to stop the motor, IP67 proximity type optional
  • Output torque limiting clutch option features quick-adjust torque setting, automatic reset every 360° & overload detect prox.
Stationary Output Flange Riser Option

This option is used if part handlers or measurement equipment are required to be mounted above the rotary indexing dial. The riser is flanged on both ends and offered in multiple lengths with a slightly smaller hollow bore than the index bore. Each riser incorporates a tolerance male centering pilot on the index output flange and for the dial plate or fixture mounting flange. The
riser is mounted to the index output flange with (4) bolts and also includes the grease fitting to be extended for easy access. Standard units are painted steel to match the beige index color but custom materials and coatings are available.

Index is shown with a riser for mounting a second fixed dial above the indexing dial. Each riser is hollow to mate to the index hollow output flange. A center pilot flange makes dial mounting concentric and precise. Dowel holes are an option.

Find more details about Sankyo AD Alpha Series - Dial Index at http://www.sankyoamerica.com

Friday, June 5, 2009

SANDEX Indexing Box

In my design, I've been using several indexing boxes from the Japanese company "Sankyo Seisakusho". The model of the indexing box is "SANDEX". It is a generic name for our cam units that combine a simple and ideal indexing mechanism, the "Roller gear cam mechanism". Sankyo's original cam technology, consisting of a roller gear cam and a follower spider (turret) is used to complete the units. SANDEX indexing units have always enjoyed high sales and are responding to industrial needs where the new technologies are evolving.

The indexing units must accommodate three types of basic motion -- that is the indexing drives with an intermittent rotating motion, the oscillating drives with their oscillating rotating motion, and the roller drives with a continuous rotating motion. SANDEX units have a higher number of indexes, index angle, and degree of design freedom than other indexing mechanisms. They are more rigid and have higher output values relative to the size of the unit, and they can eliminate backslash completely, performing at high-speed. A broad lineup of models and sizes will meet the needs of automated rotary machines of all sizes and specifications from the world smallest miniature indexes to the largest class of super-size indexes.

In addition, one model with parallel input/output shafts is also available, using a parallel mechanism as an "ideal flat cam". This is optimum for Conveyer drives with a large feed pitch or indexing drives with relatively long stopping interval.

This is the example of indexing movement (intermittent rotation).



More details about how to select the indexing drive and calculation example, please visit Ezy Mechanic.

Source: http://www.sankyo-seisakusho.co.jp/english/2index.htm