電腦顯示器底座注射模具設(shè)計及分析【含CAD圖紙+文檔】

壓縮包內(nèi)含有CAD圖紙和說明書,均可直接下載獲得文件，所見所得，電腦查看更方便。Q 197216396 或 11970985 Injecting Design Into the Molding Process There are a number of factors medical device manufacturers need to consider when using injection molded parts in their device, If they dont, they may he caught by surprise when they think they are ready to move into full production on a part. This article reviews the potential concerns that must he addressed early in the design process. By Nicole Hamilton Bernheimer and Philip BlyskalMedical device companies are always under pressure in two key areas: time and cost.Time delays in the production cycle can substantially affect product introduction timetables, and consequently, revenue. One area where medical device companies often lose valuable time, experience cost overruns, and face production delays is in poor design of injection molded components related to the mechanical functioning of the mold.Illustration of an injection molding systemInjection mold fabrication is widely used in medical device manufacturing because of its versatility.Many different types of plastics can once a mold is made, an extremely large number of pieces can be manufactured with it. Because of this,injection molding manufacturing is extremely cost effective in high volume production. But the properties of injection molding (plastic resin is fed into the injection machine, heated, and forced at high pressure into the mold by a screw and cures on cooling), and the mechanics of molding, dictate that designers pay particular attention to certain principals to ensure successful manufacture. Often medical device designers know basic injection mold design rules but this may not be enough to ensure smooth manufacture of parts and guarantee that the mechanical functioning of the mold does not cause problems.Much of the specifics of mold design have to do with the particular characteristics of thermoplastics.Thermoplastics are heated, melted,and then injected at high pressure into the mold. They cure upon cooling and parts shrink during this cooling time. The variation in shrinkage that can occur must be a major consideration for a designer in order to achieve dimension control, hold tolerances, and avoid warpage. This shrinkage is due to a number of variables : The type of plastic used The rate of cooling in the mold The wall section dimensions The gate location and the related flow characteristics in the mold The molding machine process parameters (such as temperature and pressure)Product designers often know the basic design rules relating to the variation in shrinkage rates for plastic parts and design accordingly.They desigh parts and assemblies with the achievable tolerances in mind and plan for steel safe construction in the mold as a means of revision to achieve the required dimensions.However, the reason that many molds see significant delays in achieving a production process is often overlooked by the product designer. These problems relate to the mold construction and how it functions. Specifically, there are three main areas of concern : Parting lines (where the mold opens) The type and location of gate(s)(opening through which plastic is forced into the part) How the part is ejected from the moldAll three of these mold design and construction features have a direct relationship to each other and to the overall look and quality of the molded part.The product designer must have an intimate knowledge of mold design and construction techniques or must use the services of a manufacturing engineer early in the design cycle in order to avoid costly and time consuming pitfalls. Altering the mold to achieve the required dimensions can be difficult at times but is generally able to be accomplished. If a major mistake occurs with any of the three areas listed above, it is possible that the mold might need major revision or to be built over again. This can result in tens of thousands of dollars,sometimes hundreds of thousands of dollars, wasted in redoing molds, in addition to revenue lost from production delays. Keeping the following issues in mind is crucial to successful medical product manufacture. Parting LinesParting lines directly affect the draft angles that are required on a part and the resulting dimensional changes. Draft angles must result in a proper slope so that the piece can eject properly and remain on the stationary side of the mold. As plastics cool, it adheres to the sides of the metal mold which can make ejection difficult or even impossible if adequate draft angles are not included.Parting lines must also be considered when determining the basic functioning of the mold, but are also very important to the cosmetics of the molded product. Parting lines will leave visible lines in the part that will obviously affect the visible surface after assembly. It may be unacceptable for certain parting line locations to appear on the exterior of a product, and design should be determined accordingly. GatingGate placement can play a big part on quality, appearance, and cycle time. It affects the flow characteristics of the plastics as it fills the mold, which is directly related to the shrinkage and the resulting part dimensions. It must also allow for adequate plastic flow distribution to ensure optimum form and strength of the part. Gate placement and type can dramatically affect cycle time for the process. Since manufacturing cost is directly related to cycle timethe faster the cycle, the lower the manufacturing costgating placement must ensure efficient and effective manufacture. Gates can also have a significant impact on the cosmetics of a part,creating a blemish where the plastic enters the part. On every part, there inevitably has to be a gate and therefore a gate mark so the placement must be strategic.A mold maker might decide to put a gate on a certain part of a mold for their convenience but this new location may be detrimental to the use of the part. Gate placement changes will affect the entire mold,which can mean much time and money wasted. Ejection A design defect that can create the biggest manufacturing problem is arguably when ejection doesnt work and/or potentially damages the part. Ejection problems (failure of the part to eject cleanly and completely from the mold without warpage or other damage) can cause significant delays in startup production and affect the cycle time for the process. Ejection also affects the cosmetics of the part due to the witness lines that arise from the use of ejector pins, etc. In some cases, ejection design problems can be fixed easier than moving the gates, but sometimes, it can affect other design issues and result in new molds being necessary. With certain parts, ejection can be more complicated and require activation from both sides of the mold. Avoid Mold Design PitfallsA designer who takes into account individual potential pitfalls can still err if the relationship between design factors is not considered since many design principals are interconnected. Gating, parting lines, and ejection are all related to each other, and a device manufacture may have used up their budget by the time they realize it, which is often at the point when they expect to go into full production. Designers often design the parts and take them to a manufacturing facility late in the game expecting production to go off without a hitch. In reality, manufacturing design should be included throughout the design process so that interactions can be taken into account in the earliest part of the design phase. Choose a manufacturing vendor or experienced consultant early on and have them do a detailed review of the interconnected factors that affect manufacture. Serious delays and expense can result from molds not working, and this can be avoided with careful planning and expertise. 成型工藝下的注射設(shè)計醫(yī)療設(shè)備制造商在他們的設(shè)備中使用的注塑件時需要考慮多項因素，如果他們不這樣做，當(dāng)他們認(rèn)為他們已經(jīng)準(zhǔn)備好并進(jìn)入全面生產(chǎn)時不考慮的因素可能令他們措手不及。本文綜述了潛在的擔(dān)憂，必須解決在設(shè)計過程的早期。尼科爾哈密爾頓伯恩海默和菲利普布雷?？坚t(yī)療設(shè)備公司總是在兩個關(guān)鍵領(lǐng)域的壓力下:時間和成本。生產(chǎn)周期時間延遲也會影響產(chǎn)品介紹時間表和收益結(jié)果。一些領(lǐng)域的醫(yī)療設(shè)備公司在欠缺設(shè)計注塑件相關(guān)的模具機械功能的經(jīng)驗，以至于生產(chǎn)延誤而導(dǎo)致失去寶貴的時間，從而使成本超支。注塑模具系統(tǒng)圖注塑模具加工因其多功能性而廣泛應(yīng)用于醫(yī)療設(shè)備制造業(yè)。許多不同類型大批量制件可以由一個塑料模具一次生產(chǎn)它。正因為此，注塑生產(chǎn)在批量生產(chǎn)中是極具成本效益的。但特性注塑成型(塑料樹脂被送入成型機，加熱，并迫使在高壓下由一個澆口進(jìn)入模具，冷卻定型)和力學(xué)的成型,要求設(shè)計師特別注意某些特性來確保成功制造。通常醫(yī)療設(shè)備的設(shè)計者知道基本的注塑模具設(shè)計規(guī)則,但是這可能不足以確保零件的制造和保證機械運作的模具不會引起問題。大部分的細(xì)節(jié)的模具設(shè)計與熱塑性塑料特殊的特征。熱塑性塑料加熱,熔化,然后塑料在高壓下進(jìn)入模具。塑料在冷卻時間內(nèi)凝固冷卻和部分收縮。對于一個設(shè)計師來說為了實現(xiàn)規(guī)?？刂啤⒖刂瞥叽缙?，并避免翹曲變形，收縮的變化的產(chǎn)生一定是主要考慮因素。而收縮是由于以下諸多因素影響的：使用塑料的類型模具的冷卻速率制件的壁厚澆口的位置和模具相關(guān)的流動特性注射機工藝參數(shù)(如溫度、壓力)產(chǎn)品設(shè)計師常常知道基本的設(shè)計規(guī)則和收縮率相應(yīng)地有關(guān)的變化對塑料零件進(jìn)行設(shè)計。他們的設(shè)計與實現(xiàn)零部件及裝配公差在規(guī)定和標(biāo)準(zhǔn)在模具設(shè)計中作為一種修正值，并達(dá)到要求的配合度。然而，在模具的顯著效率下在實現(xiàn)生產(chǎn)過程中經(jīng)常被產(chǎn)品設(shè)計師忽視的理由。這些問題涉及到模具結(jié)構(gòu)和功能。具體來說,涉及到以下三個主要方面：分型面澆注位置和方式如何頂出制件這三個方面如何設(shè)計的在模具設(shè)計中直接關(guān)系到產(chǎn)品的整體外觀和質(zhì)量的好壞。所以產(chǎn)品設(shè)計師必須是一個非常熟悉模具設(shè)計和成型工藝的，如果在模具設(shè)計完成后再改變這三個方面的設(shè)計，這會導(dǎo)致時間的浪費和成本的提高，這會導(dǎo)致數(shù)萬美元,有時甚至數(shù)十萬美元浪費在重作模具上。因此，設(shè)計師必須在設(shè)計周期之前就要著手解決以上所提到的三個問題。以下議題是保持醫(yī)療產(chǎn)品制造成功的關(guān)鍵。分型面在分型面的設(shè)計中，脫模斜度是最主要和最直接影響設(shè)計的因素，分型面必須有一定的脫模斜度，如果沒有一定的脫模斜度，在注塑完成后，開模時制件包緊在動模一側(cè)就很難脫模甚至于不能脫模。分型面的位置也必須考慮在確定模具的基本運作前，一些不正確的分型面在分模后可能會在制件的表面看的一條明顯的痕跡，在一些表面精度要求高的產(chǎn)品中，在外觀上出現(xiàn)這樣一個分模線可能是不可以接受的，在設(shè)計之前必須注意到這個問題。澆注位置和方式澆注位置和方式在制件質(zhì)量、外觀和周期時間上影響很大。它在塑料填充模具時影響的塑料的流動特性,直接相關(guān)的收縮率,以及部分維度。它還必須充分考慮塑性流動分布以確保最佳澆注形態(tài)和力學(xué)分布。澆注位置和類型可以極大地影響周期時間的過程。因為制造周期的長短直接影響生產(chǎn)成本，要降低制造費用，澆注位置必須確保高效和有效。澆口在一些產(chǎn)品的生產(chǎn)中有很大的影響，創(chuàng)建一個點澆口將塑料注射到模具中。在每一個塑料制品中不可避免的會產(chǎn)生一個澆注時產(chǎn)生的澆口痕跡，因此在澆口的位置選擇上必須的合理的。模具制造商可能結(jié)合制件的使用條件而決定把模具的澆口位置設(shè)計在方便制件使用的位置上。然而澆口位置變化將影響到整個模具,這也意味著大量的時間和金錢浪費了。頂出方式頂出裝置不能有效將制件頂出或者使制件在頂出是產(chǎn)生質(zhì)量問題是設(shè)計制造中的最大缺陷。頂出缺陷（在制件表面產(chǎn)生刮痕，或者使制件翹曲，壓裂等其他傷害）可導(dǎo)致影響周期的長短和成本的提高。如果設(shè)計師使用頂針頂出的方式，頂出時也會影響制件表面有痕跡或其他缺陷。在某些情況下，在固定澆口中，設(shè)計頂出方式遇到的問題比移動澆口簡單得多。但有時候，它會影響其他的設(shè)計導(dǎo)致模具出現(xiàn)其他設(shè)計問題，頂出設(shè)置要求復(fù)雜還是靈活完全取決于模具。避免模具設(shè)計陷阱一個設(shè)計師考慮個人潛在誤區(qū)仍然可能犯錯。如果設(shè)計的影響因素之間的關(guān)系并不被認(rèn)為是由于許多設(shè)計主體相互聯(lián)系的，澆注、分型面和頂出都是彼此相關(guān)，當(dāng)他們意識到一個設(shè)備制造可能使用預(yù)算的時候，他們就清楚哪一個才算希望他們?nèi)ト嫔a(chǎn)的。設(shè)計師通常在設(shè)計一個產(chǎn)品后把它拿到生產(chǎn)制造處，希望生產(chǎn)制造處能用合適的工藝把產(chǎn)品順利的制造出來。然而在實際生產(chǎn)中，設(shè)計和制造應(yīng)該是一個整體的過程，在設(shè)計的早期就應(yīng)該選擇一個有豐富經(jīng)驗的顧問的制造廠商，以便于互相交流，做一個詳細(xì)的設(shè)計制造方案，在仔細(xì)的規(guī)劃和專業(yè)知識下可以避免時間的浪費和費用的提高及模具的實用性。